sql中的d
Begin
...
End
之间的是⼀个语句块,⼀般End⽤在（相当于  {}）
while
if等语句中
在T_SQL中,if/while后只能紧跟⼀条sql语句，如果有多条则应该⽤d包含起来
如:
if (@int > 9)
set @int = 1
else
set @int = 0
这⾥的if后⾯只把变量@int设为1，没有其它的操作，所以这⾥可以省去d
但如果有多条，如
if(@int > 9)
begin
set @int = 1
select * from tablename
end
这⾥就必须⽤d
否则
select语句就永远都会被执⾏⼀次
应⽤于mybatis  当有多个delete时：
<delete id="deleteHdsqByProcessinstid">
sql中delete用法BEGIN
delete from wfworkitem c where c.processinstid in (select b.processinstid from wfprocessinst b where
b.PARENTPROCID=#processinstid#);
delete from wfactivityinst c where c.processinstid in (select b.processinstid from wfprocessinst b where
b.PARENTPROCID=#processinstid#);
delete from wftransctrl e where e.processinstid in (select b.processinstid from wfprocessinst b where b.PARENTPROCID=#processinstid#); delete from wftransition g where g.processinstid in (select b.processinstid from wfprocessinst b where
b.PARENTPROCID=#processinstid#);
delete from wfwiparticipant i where i.processinstid in (select b.processinstid from wfprocessinst b where
b.PARENTPROCID=#processinstid#);
delete from wfprocessinst a where a.processinstid in (select b.processinstid from wfprocessinst b where
b.PARENTPROCID=#processinstid#);
delete from wfworkitem where processinstid=#processinstid#;
delete from wfactivityinst where processinstid=#processinstid#;
delete from wftransctrl where processinstid=#processinstid#;
delete from wftransition where processinstid=#processinstid#;
delete from wfwiparticipant where processinstid=#processinstid#;
delete from wfprocessinst where processinstid=#processinstid#;
END;
</delete>

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