Joins And Parentheses

Kevin Feasel

2017-12-08

T-SQL

Shane O’Neill walks through different ways of grouping tables in a SQL query:

Asker: that’d be awesome if i can inner join two other tables instead of the table mentioned after FROM keyword
Me: …wait, what?
A: He’s asking
t1 left join t12
t1 left join t13
t12 inner join t13
M: em…it’s possible but it’s…iffy
A:  i wanna learn it.
do your magic

I’ve seen this in action before, but rewrote the queries not to do this.  The problem is that as the query gets more complicated, it becomes much harder to diagram things mentally.  I don’t think I’ve seen a use yet that I couldn’t rewrite to be simpler.

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