sql - what is the difference in writing styles of these 2 queries? -


i using ms sql server 2012:

the 2 queries are:

1:

with cte (  <some code> ) delete p table p join cte on p.id=cte.id , p.date>cte.date

2:

with cte (  <some code> ) delete p table p join cte on cte.id=p.id , cte.date>p.date

the difference in 2 queries writing join condition of either of table columns first.

how should decide efficient or correct?

the equality = operator symetric. flipping order of operands doesn't have functional or performance impact.

the greater (>) operator, on other hand, is, of course, not symertic. p.date>cte.date , cte.date>p.date functionally different, , should choose correct 1 according business logic, regardless of performance. no matter how fast delete statement runs, if it's deleting wrong thing, it's pretty useless (not mention down right harmful).


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