Not before the exists with the not in the same with a field?

CodePudding user response:

SQL is too long, it is suggested that reduce the text content,

CodePudding user response:

Don't need to add field
Not the exists () is a condition
For example:
SELECT 1 FROM T1 WHERE NOT the EXISTS (SELECT 1 FROM T2 WHERE T1. ID=T2. ID)
;