差: c1-c2:select * from t1 where not exists(select 1 from t2 where t1.c1=t2.c1 and t1.c2=t2.c2)c2-c1:select * from t2 where not exists(select 1 from t1 where t1.c1=t2.c1 and t1.c2=t2.c2)
select * from b where 主键 not in (select 主键 from a)或:差: c1-c2:select * from t1 where not exists(select 1 from t2 where t1.c1=t2.c1 and t1.c2=t2.c2)c2-c1:select * from t2 where not exists(select 1 from t1 where t1.c1=t2.c1 and t1.c2=t2.c2)
是关系的差运算: select * from b where not exists(select 1 from a where b.c1=a.c1 and b.c2=a.c2)
select * from b where 主键 not in (select 主键 from a)
差:
c1-c2:select * from t1 where not exists(select 1 from t2 where t1.c1=t2.c1 and t1.c2=t2.c2)c2-c1:select * from t2 where not exists(select 1 from t1 where t1.c1=t2.c1 and t1.c2=t2.c2)
c1-c2:select * from t1 where not exists(select 1 from t2 where t1.c1=t2.c1 and t1.c2=t2.c2)c2-c1:select * from t2 where not exists(select 1 from t1 where t1.c1=t2.c1 and t1.c2=t2.c2)
select * from b where not exists(select 1 from a where b.c1=a.c1 and b.c2=a.c2)