在使用mysql来处理问题时,出现的错误提示:
[SQL] create trigger Category_del
before delete on category
for each ROWIF EXISTS(select* from blog.categoryid=OLD.id)
delete from blog where categoryid=OLD.id[Err] 1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '.id)
delete from blog where categoryid=OLD.id' at line 5业务意思:
当删除category表时,如果blog中的categoryid字段与category中的id字段相同时,如果删除category时,同时删除
blog相应的一行记录!
[SQL] create trigger Category_del
before delete on category
for each ROWIF EXISTS(select* from blog.categoryid=OLD.id)
delete from blog where categoryid=OLD.id[Err] 1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '.id)
delete from blog where categoryid=OLD.id' at line 5业务意思:
当删除category表时,如果blog中的categoryid字段与category中的id字段相同时,如果删除category时,同时删除
blog相应的一行记录!
IF EXISTS(select* from blog where categoryid=OLD.id)
delete from blog where categoryid=OLD.id
before delete on category
for each ROW
delete from blog where categoryid=OLD.id;
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2:FROM后面要跟表名称,不是字段名称。缺少FROMcreate trigger Category_del before delete on category
for each ROWIF EXISTS(select * from blog where categoryid=OLD.id) then
delete from blog where categoryid=OLD.id ;
end if;
for each ROWIF EXISTS(select * from blog where categoryid=OLD.id) then
delete from blog where categoryid=OLD.id ;
end if;要加THEN