Over 300% faster results. Performance : Where vs JOIN. If the view has multiple base tables, the optimizer can push the join predicate into the view. Preferences Newsletters Community Log Out. Being involved with EE helped me to grow personally and professionally. INNER join and OUTER join will give you results differently, so you can’t replace an INNER join with an OUTER join as it will change your business logic itself. a transaction table), and then left join B to reference table C, etc. A join will be performed whenever multiple tables appear in the FROM clause of the query. I think if you are noticing a 10-20% difference between a view and a join, then you are not making an *exact* comparison between the two. Specifying a logical operator (for example, = or <>,) to be used in co… Some questions never get old and some question and I believe we will be discussing them for many more years in the future. WHILE loop performance in SQL Server 2008. by Tim Chapman in The Enterprise Cloud … This blog presents tips to increase SQL Server stored procedure performance by using SET NOCOUNT ON, schema name before objects, EXISTS instead of COUNT (), NO LOCK, Join query, avoid Select *, avoid temp temporary table, create Proper Index. Furthermore, these statistics can be maintained and kept up-to-date to ensure that the Query Optimizer will create the best guesses when fetching data. These differences result from the fact that database optimizers only interpret the WHERE clause of VIEW to determine the first access. “Is there a performance difference between putting the JOIN conditions in the ON clause or the WHERE clause in MySQL?” No, there’s no difference. Like (0) Former Member Post author. But when you get implicit conversions, or you have to put in explicit conversions, you’re performing a function on your columns. There are many different scenarios when an index can help the performance of a query and ensuring that the columns that make up your JOIN predicate is an important one. A bit obvious in hindsight. We may see the physical join implementations with names like nested loops, sort merge and hash join. Attachments: By using joins, you can retrieve data from two or more tables based on logical relationships between the tables. To that end, SQL Server, Oracle, etc. I am guessing based on your initial response the view is better performance. I took the qry with the views and started substituting directly from the view definition untill there were no more views. You can easily adapt it to the requirements of a specific application. SQL Performance of Join and Where Exists. More. Help to improve this answer by adding a comment. In that case just for fun guess one option LEFT JOIN or NOT IN. Up to 10 attachments (including images) can be used with a maximum of 1.0 MB each and 10.5 MB total. You already have an active moderator alert for this content. Explanation . It was using a big table generated by a schema-bound VIEW and there weren’t only four cases to consider (although there were four potential columns to JOIN upon). The data stays in the tables. Hidden page that shows all messages in a thread. Get to release 11g and use the View join elimination feature. The answer is: It depends! Your statement "you are joing two tables and storing result in a view" needs a bit of elaboration. Tks R for suggesting the explain plan. A few of these have come across dotnetkicks in the past month or so (including one from me where I was ranting about the Unknown result from a programmer's standpoint). Find customers who’ve placed an order, products categorized as books, or cities that have airports. If they don't can you give an example/breakdown of how to rewrite in 8i.Thanks in advance, Left Join vs Left Outer Join. The question was about Performance Comparison IN vs OR. Performance is a big deal and this was the opening line in an article that was written on How to optimize SQL Server ... but this time we’ll also show where they’re stored in SQL Server and how to view them. 1238. A VIEW can be created in the DBMS, and each view represents a particular SQL query. You should only submit an answer when you are proposing a solution to the poster's problem. Note: *There is an exemption from 6(b) for medium-sized companies Source: Companies Act 2006, section 417(6) 6. The purpose of a view is to use the query over and over again. 1131. (Unlock this solution with a 7-day Free Trial). In a thread titled "Subquery or Join Performance", a challenge to beat subquery performance with a join is off topic? “Key performance indicators” means factors by reference to which the development, performance or position of the business of the company can be measured effectively. Number of Region Servers: 4 (HBase heap: 10GB, Processor: 6 cores @ 3.3GHz Xeon) Phoenix vs Impala (running over HBase) Query: select count(1) from table over 1M and … While joins are very common and powerful, they warrant special performance consideration as they may require large network transfers or even create datasets beyond our capability to handle. March 20, 2007 at 4:27 am . Join Performance: ON vs WHERE ¶ Now that we are equipped with a better appreciation and understanding of the intricacies of the various join methods, let’s revisit the queries from the introduction. The query parts of the view definitions will be performed upon materializing it and there you save the time in your production queries. From "Design, Implementation, and Analysis of Performance-Optimized Programs" on service.sap.com/performance. Connect with Certified Experts to gain insight and support on specific technology challenges including: We help IT Professionals succeed at work. Use it in your parameters and in your variables. Home Archives Authors Categories Newsletters Latest Builds About Q & A Community GO. On Fri, Sep 11, 2009 at 5:01 PM, Merlin Moncure wrote: > On Fri, Sep 11, 2009 at 2:56 PM, Jason Tesser > wrote: > > OK so in my case I have a Person, Email, Phone and … The merge method is more versatile and allows us to specify columns besides the index to join on for both dataframes. JOIN performance has a lot to do with how many rows you can stuff in a data page. Phoenix vs Hive (running over HDFS and HBase) Query: select count(1) from table over 10M and 100M rows. How to list the tables in a SQLite database file that was opened with ATTACH? yes Query 2 much faster than Query 1, because in Query 1 uses Correlated Sub queries, uses Table Scan. At least I have always missed the technical settings button, so I assumed it would not be possible. If you think my suggestion is useful, please rate it as helpful. The following queries are algebraically equivalent inside MySQL and will have the same execution plan. From Oracle's point of view, these queries are identical.Oracle just sees that they are the same and can avoid the whole query evaluation at all: it just uses index access.. Now let's see how smart Oracle will be when it will have to search for a non-indexed column which, in addition, contains duplicates.. JOIN / DISTINCT on a non-indexed column We've partnered with two important charities to provide clean water and computer science education to those who need it most. Joins indicate how SQL Server should use data from one table to select the rows in another table. You can use a materialzed view to get some performance. @williamplunkett from a performance standpoint, is there a difference in creating a view that contains a (inner) join and when needed just reading the 1st table to get the foreign key and then reading the second table?. In that case just for fun guess one option LEFT JOIN or NOT IN. The issue with the SQL appears to be a Merge Join (Inner Join) and I am not sure on the best way to try and improve the performance of these. "With group requests from different tables, use JOINs or VIEWs. SQLPerformance delivers innovative and practical solutions for improving SQL Server performance. These are the types of queries I will be doing though. From what I can tell, the view _name_ implied table A, but they then wanted to right join to a main table B (e.g. 1568. Try to use Calculation view for all the modelling and design that involves complex calculations and data massaging. This articles gives you a performance comparison for NOT IN, SQL Not Exists, SQL LEFT JOIN and SQL EXCEPT. I would really appreciate someone pointing me in the right direction or if there is any more information I can provide then please let me know. In this blog post we'll go over the issue and take a look at how it was resolved using the new sub-query capability in CrateDB as an alternative to using a left join. First, let’s assume there there is an index on department_id in both tables. Commented: 2002-11-19. As far as I know there is no difference in performance, only in reusability. Share a link to this. SQL INNER JOIN vs Where Exists Performance Consideration. 2. If you want to use it only in one of your program, join is easier....and you can use inner/outer join in you program, based on your needs. To create an index on a view, the view … I believe you are comparing chalk with cheese, a view is a filtered select, a join is self explanitory. Hello all, I'm aware Views should always be considered before trying Table-Valued function as they gain in performance in several aspects. a transaction table), and then left join B to reference table C, etc. A join is a query that combines records from two or more tables. Below are charts showing relative performance between Phoenix and some other related products. As far as I know there is no difference in performance, only in reusability. will typically provide a "cached" or "compiled" version of your view, thus improving its performance. If I’m off base, let me know. Der Eurofighter gilt als das modernste Kampfflugzeug der Welt - der Joint Strike Fighter als das beste Stück amerikanischer Luftfahrttechnik. First, let’s assume there there is an index on department_id in both tables. 1 In core Spark it can be more important to think about the ordering of operations, since the DAG optimizer, unlike the SQL optimizer, isn’t able to re-order or push down filters. The join method works best when we are joining dataframes on their indexes (though you can specify another column to join on for the left dataframe). 0. mcgurk 2007-05-18 re: SQL Server: JOIN vs IN vs EXISTS - the logical difference Very nice article. For example, let’s say you want to JOIN two tables. View full profile. A few of these have come across dotnetkicks in the past month or so (including one from me where I was ranting about the Unknown result from a programmer's standpoint). Preferences Newsletters Community Log Out. I'm not sure, if views are (without doubt) always faster than joins - runtime depends much more on join and where-clause, usable indices and so one. Join Performance: ON vs WHERE ¶ Now that we are equipped with a better appreciation and understanding of the intricacies of the various join methods, let’s revisit the queries from the introduction. Wednesday, June 24, 2009 12:34 AM. COVID-19 ... , which can degrade transaction performance. Though personally, I have answered this question quite a many times before, let us answer it once … If you have an answer for this question, then please use the Your Answer form at the bottom of the page instead. Join / Log In View full profile. Help to improve this question by adding a comment. How the performance of a table Vs Indexed view. Exactly same query plan. >>run explain plan on the view and the join and see the results...they should be the same. A curious position, to be sure. This technical explanation is very important for better understanding of how joins and indexes work: Unlike Inner joins where only common rows are … Try using Star-join instead of joining multiple nodes of master data/dimensions to a fact table of measures. I recently had a developer come to me with a poorly performing query. Know someone who can answer? If the index gets reset to a counter post merge, we can use set_index to change it back. CHAPTER 9 Joint Product and By-Product Costing In Brief Some products are produced jointly with other products. I know that SQL Server can implicitly convert from one to another. Starting in 11g, the optimizer is intelligent and it will detect situations where view data is not needed in the result set, and btpass processing of that data, thereby greatly improving performance of queries with views. It is like having another employee that is extremely experienced. Our friends at Gestalten.de, a design and software agency in Germany, pinged us recently on Github for some CrateDB query performance help. It is accessed at runtime from these underlying tables. Posted on December 29, 2016 March 31, 2017 by Eric Cobb. Therefore, you should take MANDT from the field list of the VIEW from the table providing the most selective first access. WITH t (customerid,lastorderdate) AS ( SELECT *, row_number() over (partition by customerid order by orderdate desc) rowno FROM sales.SalesOrderHeader WHERE customerid=27604 GROUP BY customerid DB View can be resued in several program. EXISTS vs IN vs JOIN with NULLable columns: After creating the same two tables, but with the ID column allowing null and filling them with the same data. If the secondary tables include MANDT in their indexes and a selective primary table cannot be determined, then you should not use a VIEW. Here you go… use the data type that is in your database. Which is more correct with SQL Functions, Join or in Where clause? Over 300% faster results. The select list of the query can select any columns from any of these tables. creating a VIEW without a doubt will be faster than the runtime JOIN created by a SELECT stmt. For VIEW, however, this WHERE clause is generated only for the table that provides MANDT in the VIEW projection list. First of all answer this question : Which method of T-SQL is better for performance LEFT JOIN or NOT IN when writing a query? If it has helped you to resolve the problem, please Mark it as Answer. SQL Query on single table-valued parameter slow on large input-1. M-Ali, I'm pretty sure its the same. Community call for creating the fastest number series generator. Performance when querying from View vs from Table. It all depends on what kind of data is and what kind query it is etc. When asked, what has been your best career decision? For a view that is on the right side of an outer join, the optimzer can use one of two methods, depending on how many base tables the view accesses: If the view has only one base table, the optimizer can use view merging. css for site-alert and hs-announce Pre-generate views. Experts Exchange always has the answer, or at the least points me in the correct direction! That does allow for nulls in table A columns referenced in the view, but the vendor was fine with that. SELECT * […] 4. Do they exist for 8i if so can you point me to the documentation. As you will see below, it’s a fairly straight forward query, consisting of one table with one join and a simple WHERE clause. The above query can be rewritten without using inner join like below but the performance will be impacted compared to inner join – SELECT s.StudentID, s.StudentName FROM tClass c , tstudent s WHERE c.ClassID = s.ClassID AND c.ClassID = 10 Left Join. Queries 1a and 1b are logically the same and Oracle will treat them that way. If you have a different answer for this question, then please use the Your Answer form at the bottom of the page instead. Query Performance - Join vs ExistsQuery Performance - Join vs Exists. How the performance of a table Vs Indexed view. It all depends on what kind of data is and what kind query it is etc. https://www.experts-exchange.com/questions/20401652/views-vs-joins-performance.html. If the two join inputs are not small but are sorted on their join column (for example, if they were obtained by scanning sorted indexes), a merge join is the fastest join operation. One small thing to mention here to make sure that all scenarios are covered is that EXISTS vs IN vs JOIN with NULLable columns will give you the same results and the same performance as what you get with NOT NULLABLE columns mentioned … Obcourse, the benefits in terms of performance will be obvious if you are accessing large number of records otherwise the a normal JOIN stmt will serve the purpose. 531. Precursor. Instead of changing the joins you have to look into other factors. Specifying the column from each table to be used for the join. mcgurk 2007-05-18 re: SQL Server: JOIN vs IN vs EXISTS - the logical difference Very nice article. there is no way to buffer views on application level (SAP Table Buffering) - is there? So, if you are the one! In this post we’ll compare the performance and execution paths of inner join … Add a column with a default value to an existing table in SQL Server. Actually since a view is simply a stored query, you should not notice any difference in performace between a query against the view and a query against the base tables. Views might be cached by application servers, joins are always accessed by database directly. Oracle joins -- including the question of LEFT JOIN vs. LEFT OUTER JOIN -- can be a very confusing topic, especially for newcomers to Oracle databases.Let's define the relevant terms and explore other commonly asked questions about Oracle joins and the JOIN syntax in PL/SQL, the vendor's implementation of SQL.. What is a JOIN clause? The problem was that this query was taking over 11 minutes to run, and only returned about 40,00 Hash joins - In a hash join, the Oracle database does a full-scan of the driving table, builds a RAM hash table, and then probes for matching rows in the other table. Comparing cursor vs. Queries 1a and 1b are logically the same and Oracle will treat them that way. Generating views based on an entity model is a significant cost the first time that an application executes a query. A typical join condition specifies a foreign key from one table and its associated key in the other table. 5. SELECT * […] I believe you are comparing chalk with cheese, a view is a filtered select, a join is self explanitory. There should be indexes on all fields used in the WHERE and JOIN portions of the SQL statement. I often have cases with three or more INNER JOINs each of them having different conditions. Rails: How to Select Records Which Don't Have a Specific Related (associated) Object (SQL EXISTS brief how-to) 0. T-SQL commands performance comparison – NOT IN vs SQL NOT EXISTS vs SQL LEFT JOIN vs SQL EXCEPT September 22, 2017 by Ahmad Yaseen. DVR . text/html 6/24/2009 12:41:39 AM masher2 0. Often in forum threads discussing query performance I’ll see people recommending replacing an INNER JOIN with an IN (or recommending replacing an IN with an INNER JOIN) for performance reasons. In general, this should perform better than a "simple" query, though if the … KR Lars. READ MORE. Gain unlimited access to on-demand training courses with an Experts Exchange subscription. Sometimes we need to identify record sets with at-least-one relationships. ". Take the 3-Minute SQL performance test. Most likely, one of these two tables will be smaller than the other, and SQL Server will most likely select the smaller of the two tables to be the inner table of the JOIN. Then, join on the Temp table so the query doesn't have to filter out so many rows from so many tables. How do I perform an IF…THEN in an SQL SELECT? From what I can tell, the view _name_ implied table A, but they then wanted to right join to a main table B (e.g. Here is the execution plan and the SQL query. Data is 5 narrow columns. But most times joins (/views) are anyway complex and need a lot of entries -> caching is not useful. Introduction. Also, please make sure that you answer complies with our Rules of Engagement. In this blog post we'll go over the issue and take a look at how it was resolved using the new sub-query capability in CrateDB as an alternative to using a left join. So me being me, I decided to look into this issue and do some testing myself. DB View can be resued in several program. view join elimination. Strategies for Improving Performance. I’m not entirely sure I understand your question. Experts: correct me if I am wrong. The T-SQL commands library, available in Microsoft SQL Server and updated in each version with new commands and … 2884. First of all answer this question : Which method of T-SQL is better for performance LEFT JOIN or NOT IN when writing a query? SQL Join vs Subquery. Once the view is created, the query it represents is hidden from the user, and instead the view appears to be just another table. Performance Problem When Using OR In A JOIN. The following queries are algebraically equivalent inside MySQL and will have the same execution plan. Michael Asher. “Is there a performance difference between putting the JOIN conditions in the ON clause or the WHERE clause in MySQL?” No, there’s no difference. I’ve heard this question a lot, but never thought to blog about the answer. For Outer Joins, the important index depends on the field of the table that we need to search in. Core Spark Joins. I only looked in this blog at the primary index. Buffering a VIEW means not only less performance improvement, but also a significant rise in memory allocation and overhead during buffer synchronization. That does allow for nulls in table A columns referenced in the view, but the vendor was fine with that. For maximum performance when joining two or more tables, the indexes on the columns to be joined should have the same data type, and ideally, the same width. If you want to use it only in one of your program, join is easier....and you can use inner/outer join in you program, based on your needs. VIEWs, like any table definition, may be used in multiple areas of the program, thus reducing the number of different statements in the statement cache. Especially when an earlier post of insults and allegations didn't raise an eyebrow? Performance of reading data from SQL Server 2005 using ADO.NET and LINQ by directly executing SQL statements. 1. The use of a conditional JOIN got the business solution working quickly, however when I tested the performance I found it wanting. Views do not store data. The challenge is on! If both join inputs are large and the two inputs are of similar sizes, a merge join with prior sorting and a hash join offer similar performance. 1. The JOIN is coded directly in ABAP. join example, new vs old syntax Hi Tom,I know in oracle9i we have the cross join and full outer join. Don't use JOINs or VIEWs over tables that are buffered with their technical settings. Please want expert on view on this. Just putting up and writing down all the consolidated best practices for HANA modelling that we witnessed for better performance. b) SELECT * FROM A INNER JOIN B ON B.ID = A.ID WHERE B.Cond1 = 1 AND B.Cond2 = 2 This is a very simple sample. Even though MANDT from each of the tables can join together the VIEW tables, significant processing differences in these tables can occur within VIEW if MANDT also appears in the indexes of the other tables that are included. You can improve the overall performance of queries in the Entity Framework by using the following strategies. As per SAP documentation "The data of a view is derived from one or more tables, but not stored physically". Gislain . I really would like to see how the Join-Performance-Comparisation looks like if the database has the right indexes in place. who feel changing the join will improve performance then you have to be cautious about this. If you mix buffered and unbuffered tables in one access rather than reading both table types, you always lose performance because the database interface will not use the existing buffers. If you want the poster to clarify the question or provide more information, please leave a comment instead, requesting additional details. Joing two tables and 10.5 MB total fact that database optimizers only interpret the WHERE and join of... Needs a bit of elaboration this point let 's take a look at a query. Application level ( SAP table Buffering ) - is there join portions of the page instead looks! More INNER joins each of them having different conditions placed an order, products categorized books! If you have to look into this issue and do some testing.... First time that view vs join performance application executes a query that you answer complies with our Rules of Engagement Exchange subscription columns... End, SQL LEFT join B of dbas didnt think of that either a to. Question, then please use the view primary index just putting Up and writing down all the from! Multiple tables appear in the correct direction less performance improvement, but never thought to blog the! A thread titled `` Subquery or join performance '', a view without a doubt will doing... ’ s assume there there is no difference in performance, only in reusability improvement, but vendor... Please rate it as helpful table providing the most efficient/elegant way to buffer views on level! Relative performance between Phoenix and some question and I believe we will be though. Anyway complex and need a lot of entries - > caching is NOT useful key in correct! On for both dataframes n't duplicate rows specific application me to view vs join performance of! Both dataframes, SQL Server, Oracle, etc m off base view vs join performance let s! That SQL Server can implicitly convert from one table and its associated in! To filter out so many rows from right table was opened with ATTACH SQL select to... Need it most some CrateDB query performance help Framework by using the following queries are algebraically equivalent inside MySQL will. Logical relationships between the tables in a thread with their technical settings button, so assumed! Its the same and Oracle will treat them that way home Archives Authors Categories Newsletters Latest about... A view '' needs a bit of elaboration runtime from these underlying tables and allows us to columns! Performance has a lot to do with how many rows you can stuff in a thread SQL statements index. Records from two or more INNER joins each of them having different conditions a of... Rows from the view, however when I tested the performance I found it wanting m-ali, 'm... Problem, please include specifics, such as step-by-step instructions, context for the join predicate into the view and... To me with a 7-day Free Trial ) an SQL select lot but! Which do n't use view vs join performance or views career decision Performance-Optimized Programs '' on service.sap.com/performance useful... The following queries are algebraically equivalent inside MySQL and will have the same view from the fact that optimizers... Assume there there is an index on department_id in both tables to improve this answer by adding a comment performance. - the logical difference Very nice article INNER joins view vs join performance of them having conditions... In order to illustrate this point let 's take a look at a simple query view vs join performance joins the Parent Child. Design, Implementation, and then LEFT join B is an equivalent syntax to a table. Let ’ s say you want to join on the view from the field of SQL! Server can implicitly convert from one to another in a join is a filtered select, a challenge to Subquery... Down all the consolidated best practices for HANA modelling that we need to identify record with! View and the SQL query that nor why a room full of dbas didnt think that. Select any columns from any of these tables MANDT in the view definition there... Recently on Github for some CrateDB query performance help and kept up-to-date to ensure the. Performance LEFT join B to reference table C, etc, I 'm pretty sure its the same execution.! To select records which do n't use joins or views over tables that are buffered with technical... Option LEFT join does n't have to look into other factors based on your initial the! S say you want to join two tables are related in a thread Rules of...., this WHERE clause is generated only for the solution, and then LEFT join be... Specifying the column from each table to select records which do n't have to be incredibly in. Faster than the runtime join created by a select stmt less performance improvement but. Got the business solution working quickly, however, is specified in the other table in WHERE?., pinged us recently on Github for some CrateDB query performance - join vs Exists - the difference... Career decision join on for both dataframes are algebraically equivalent inside MySQL and have... Answer this question: which method of T-SQL is better for performance join! They should be the same best practices for HANA modelling that we need to in! A SQLite database file that was opened with ATTACH what is the execution plan your statement `` you are two... Full of dbas didnt think of that nor why a room full of dbas didnt of! As books, or cities that have airports when writing a query that combines records from or! Query optimizer will create the best guesses when fetching data so many tables condition defines the way two tables storing... M NOT entirely sure I understand your question last Updated: 03 May, 2020 ; what are joins substituting! List the tables in a join end, SQL Server comparison for NOT in I always. About Q & a Community GO grow personally and professionally end, SQL join... From so many tables caching is NOT useful re: SQL Server: join vs Exists answer... The select list of the table that we need to search in SQL select version of view... Query optimizer will create the best guesses when fetching data join elimination feature changing... A doubt will be doing though by a select stmt adapt it to poster. Columns besides the index gets reset to a fact table of measures here is the most efficient/elegant way to a. An existing table in SQL Server, Oracle, etc optimizer will create the best when! Help to improve this question by adding a comment result set small by including a ParentID in! Technical settings button, so I assumed it would NOT be possible used with a value... Result set small by including a ParentID filter in the future about Q & a GO. Better performance apply LEFT outer join and matching rows from the LEFT and! View has multiple base tables, the optimizer can push the join and SQL EXCEPT other! Take a look at a simple query that joins the Parent and Child tables join portions the... Mysql and will have the same execution plan and the join will return all the rows in another.. Experts to gain insight and support on specific technology challenges including: we it. From two or more INNER joins each of them having different conditions select stmt in SQL Server Oracle! Das beste Stück amerikanischer Luftfahrttechnik your initial response the view projection list these differences result the... Queries 1a and 1b are logically the same execution plan and the join predicate into the view definition untill were! Ve placed an order, products categorized as books, or at the least points me in the.! Subquery performance with a maximum of 1.0 MB each and 10.5 MB total first, let ’ s say want... An existing table in SQL Server, the important index depends on what kind query it like. And its associated key in the view a challenge to beat Subquery performance with a maximum of 1.0 each...: select count ( 1 ) from table over 10M and 100M rows why... I assumed it would NOT be possible however when I tested the performance I found it wanting at-least-one relationships we... Received this question: which method of T-SQL is better performance a typical join condition specifies a foreign key one! More views the logical difference Very nice article join predicate into the view projection list the views and started directly... Categorized as books, or cities that have airports on your initial response the view has multiple base tables the! Other table in SQL Server, the keyword outer is optional when you are comparing chalk with cheese a... As I know there is no difference in performance, only in reusability / join! I received this question: which method of checking view vs join performance INNER / join! Always missed the technical settings button, so I assumed it would NOT be possible SQL! An answer when you apply LEFT outer join B to reference table C, etc join... In when writing a query that joins the Parent and Child tables and then LEFT join is! The important index depends on what kind of data is and what kind query it accessed... Lot of entries - > caching is NOT useful grow personally and professionally active moderator view vs join performance! Or provide more information, please make sure that you answer complies with our Rules of Engagement have always the... Following strategies and see the results... they should be indexes on all fields used in the direction! Use a materialzed view to determine the first access a specific related ( associated ) (... Unlimited access to on-demand training courses with an Experts Exchange subscription unlimited access to on-demand training with! Where clause the same and Oracle will treat them that way gives you a performance comparison in vs or Functions. Performance I found it wanting that combines records from two or more tables based on your initial response the view vs join performance.