Comments on: Execution plan operations – joins

By: Merge join Vs Hash join Vs Nested loop join « SqlserverBlogForum

Merge join Vs Hash join Vs Nested loop join « SqlserverBlogForum — Tue, 04 Oct 2011 20:10:48 +0000

[...] more: Read Gail Shaw’s blog. It has Craig Freedman’s link too. Why I gave Gail’s link instead of directly give [...]

By: Gail

Gail — Thu, 28 Jul 2011 11:21:53 +0000

If you hover the mouse over, the tooltip will tell you what the problem is.

By: behnaz

behnaz — Thu, 28 Jul 2011 07:41:14 +0000

would you tell me what is the exclamation mark some times is seen in nested loops inner join pls?

By: Tim

Tim — Fri, 27 May 2011 17:43:00 +0000

Great intro – just what I needed.

By: Gail

Gail — Fri, 20 May 2011 19:31:03 +0000

Not quite

The one resultset is used to form a hash table (wikipedia should have a good coverage of how a hash table works), then the second resultset is hashed to figure out which bucket the value belongs in. It’s a single pass over each resultset.

Nested loop is an O(n^2) algorithm, hash search is much lower than that.

By: Garry

Garry — Fri, 20 May 2011 16:18:08 +0000

Is the hash join not similar to the nested loop in that it compares each hashed value to each row in the hash table ? ie does it not have to loop to do this ? Trying to understand the difference besides the fact that one hashes the values whereas the other compares the actual values.

By: Some interesting articles.. « QuantuMatrix’s Weblog

Some interesting articles.. « QuantuMatrix’s Weblog — Wed, 25 Nov 2009 21:39:44 +0000

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