MySQL - EXISTS 和 NOT EXISTS

语法规则：

 

SELECT * FROM tableName t WHERE 1 = 1 AND 2 = 2 AND EXISTS (SELECT * FROM tableName t2 WHERE t.id = t2.proj_id)

 

SELECT * FROM tableName t WHERE 1 = 1 AND 2 = 2 AND NOT EXISTS (SELECT * FROM tableName t2 WHERE t.id = t2.proj_id)