代码:
create table coltype (coltype varchar(5));
insert into coltype values ('typ1');
create table colsubtype (coltype varchar(5), colsubtype varchar(5));
insert into colsubtype values ('typ2', 'st1');
insert into colsubtype values ('typ2', 'st2');
create table table1 (col1 varchar(5), coltype varchar(5), colsubtype varchar(5));
insert into table1 values ('val1','typ1', 'st1');
insert into table1 values ('val2','typ1', 'st2');
insert into table1 values ('val3','typ1', 'st3');
insert into table1 values ('val4','typ2', 'st1');
insert into table1 values ('val5','typ2', 'st2');
insert into table1 values ('val6','typ2', 'st3');
insert into table1 values ('val7','typ3', 'st1');
insert into table1 values ('val8','typ3', 'st2');
insert into table1 values ('val9','typ3', 'st3');
commit;
基本上,我想删除 coltype
所在的所有记录和colsubtype
coltype
中没有提到和colsubtype
表。
我该怎么做。下面是我正在考虑采取的路径,但它不起作用 - 而且 - 它看起来不是一个好的设计。
delete from table1
where coltype != (select coltype from coltype)
OR not (coltype = cst.coltype and colsubtype = cst.colsubtype
from (select coltype, colsubtype from colsubtype) cst)
最佳答案
使用 NOT EXISTS:
delete from t1
from table1 t1
where not exists (select null from coltype ct where ct.coltype = t1.coltype)
or not exists (select null from colsubtype cst where cst.colsubtype = t1.colsubtype)
使用左连接:
delete from t1
from table1 t1
left join coltype ct
on t1.coltype = ct.coltype
left join colsubtype cst
on t1.colsubtype = cst.colsubtype
where ct.coltype is null
or cst.colsubtype is null
关于sql-server - 通过连接删除多个表,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/4649547/