SQL Joins and Where clauses
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I've not taken any classes on SQL, just learned hands on. I was trying to fix a query for someone and they had written their Joins in a fashion I was not used to.
For example, I write ALL of my Join statements then put one Where with Ands at the very end.
This individual had placed some Where clauses in a couple of the joins. And these "where" clauses as I see, would normally just be below at the end of all the Joins.
So does SQL Developer read the Where/ands as it does each Join above? Or is it more efficient to put Where's below each Join?
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Are you looking to replicate the joins and where clause in Designer, or is this a general SQL syntax question? In Alteryx, I recommend having the where clauses embedded into the input. From there, you will be joining only a subset of the records and will make processing more efficient.
With regard to SQL syntax, something like Stackoverflow may be a more appropriate place for your question.
https://stackoverflow.com/questions/354070/sql-join-where-clause-vs-on-clause
https://stackoverflow.com/questions/15483808/sql-join-where-to-place-the-where-condition
Hope this helps!
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Thanks. I was searching the web for a SQL answer, but answers are always scattered and on this, nothing hit.
Your second link was helpful on the SQL side.
This persons answer, hopefully correct, is what I was looking for:
"I think the faster way is to put the filter in the where clause, because it will procees that filter in the where first , and then the join clause, so there will be no need of permutation of filters." - Artemination
I use a lot of SQL statements to bring in data.
