join-hints

SQL SERVER 2008 JOIN hints

由 北城以北 提交于 2019-12-31 02:09:06
问题 Recently, I was trying to optimise this query UPDATE Analytics SET UserID = x.UserID FROM Analytics z INNER JOIN UserDetail x ON x.UserGUID = z.UserGUID Estimated execution plan show 57% on the Table Update and 40% on a Hash Match (Aggregate). I did some snooping around and came across the topic of JOIN hints. So I added a LOOP hint to my inner join and WA-ZHAM! The new execution plan shows 38% on the Table Update and 58% on an Index Seek. So I was about to start applying LOOP hints to all my

When should I use an INNER -LOOP- JOIN instead of an INNER JOIN

由 前提是你 提交于 2019-11-30 04:34:40
Today I learned about a thing in SQL Server called INNER LOOP JOIN . What does this mean? (Google is not helping .. or should I say ... the blog posts about it are a bit .. technical and are blowing my mind). Also, what are some common scenarios that would be a good idea to use an INNER LOOP JOIN over a standard INNER JOIN ? Ash LOOP | HASH | MERGE are Join hints, specifying that the join in the query should use looping, hashing, or merging. Using LOOP |HASH | MERGE JOIN enforces a particular join between two tables. LOOP cannot be specified together with RIGHT or FULL as a join type. You

Loop Join in SQL Server 2008

由 自作多情 提交于 2019-11-29 12:43:15
问题 I'm not clear about working difference between queries mentioned below. Specifically I'm unclear about the concept of OPTION(LOOP JOIN) . 1st approach: it's a traditional join used, which is most expensive than all of below. SELECT * FROM [Item Detail] a LEFT JOIN [Order Detail] b ON a.[ItemId] = b.[fkItemId] OPTION (FORCE ORDER); 2nd approach: It includes OPTION in a statement with sorted data, merely optimized. SELECT * FROM [Item Detail] a LEFT LOOP JOIN [Order Detail] b ON a.[ItemId] = b.

When should I use an INNER -LOOP- JOIN instead of an INNER JOIN

由 ℡╲_俬逩灬. 提交于 2019-11-29 01:43:46
问题 Today I learned about a thing in SQL Server called INNER LOOP JOIN. What does this mean? (Google is not helping .. or should I say ... the blog posts about it are a bit .. technical and are blowing my mind). Also, what are some common scenarios that would be a good idea to use an INNER LOOP JOIN over a standard INNER JOIN ? 回答1: LOOP | HASH | MERGE are Join hints, specifying that the join in the query should use looping, hashing, or merging. Using LOOP |HASH | MERGE JOIN enforces a particular
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