forxin(select*from rollup)loopif(notexists(that query))thenOUTPUTendif;end loop; 注意:NOT EXISTS 与 NOT IN 不能完全互相替换,看具体的需求。如果选择的列可以为空,则不能被替换。 例如下面语句,看他们的区别: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 s
Query OK,1rowaffected (0.07sec) greatsql>select*fromt1wheret1.c2notin(selectt2.c2fromt2wheret2.c2isnotnull); +---+---+ |c1|c2| +---+---+ |2|b| +---+---+ 1rowinset(0.00sec) greatsql>select*fromt1wherenotexists(select1fromt2wheret2.c2=t1.c2); +---+---+ |c1|c2|...
加热IN (“coal”, “wood”) -> UNKNOWN,用SQL表示加热为NULL时,NULL可能是coal,也可能是wood,或者不是,我们不知道… 加热NOT IN (“coal”, “wood”) -> UNKNOWN 因为NOT IN应用于NOT且IN是UNKNOWN,所以NOT(UNKNOWN)是UNKNOWN。 作为结果: 因为WHERE消除了条件不为TRUE的行,所以消除了房屋A。从SQL的角...
for x in ( select * from rollup ) loop if ( not exists ( that query ) ) then OUTPUT end if; end loop; 注意:NOT EXISTS 与 NOT IN 不能完全互相替换,看具体的需求。如果选择的列可以为空,则不能被替换。 例如下面语句,看他们的区别: select x,y from t; 查询x和y数据如下: ...
querywrapper notinsql 文心快码BaiduComate QueryWrapper的概念和用途 QueryWrapper是MyBatis-Plus提供的一个条件构造器,用于构建SQL查询条件。它极大地简化了SQL查询的编写过程,使得开发人员可以通过链式调用的方式灵活地组合各种查询条件,而无需直接编写复杂的SQL语句。QueryWrapper支持多种查询条件,如等于、不等于、大于、...
$sql="select count(qID) from test_querys where isTested=1and qID<=$maxID and qID>=$minID and qID not in (select distinct qID from $left_cr where isSubmit=1 and qID<=$maxID and qID>=$minID)"; $sql="SELECTcount(a.qID) from test_querys ASa left join (select qID from $left...
2.NOT IN 与NOT EXISTS: NOT EXISTS的执行流程 select ... from rollup R where not exists ( select 'Found' from title T where R.source_id = T.Title_ID); 1. 可以理解为: for x in ( select * from rollup ) loop if ( not exists ( that query ) ) then OUTPUT...
cat repo_ora_6702_10053c.trc 在 "Final query after transformations" 部分即为优化器改写后的SQL,关联条件也是等值查询: Final query after transformations:*** UNPARSED QUERY IS *** SELECT "T_LDIM_AGENT_UPREL"."AGENT_ID" "AGENT_ID",MAX("T_LDIM_AGENT_UPREL"."REL_AGENT_ID") "MAX(REL_...
cat repo_ora_6702_10053c.trc 在 "Final query after transformations" 部分即为优化器改写后的SQL,关联条件也是等值查询: Final query after transformations:*** UNPARSED QUERY IS *** SELECT "T_LDIM_AGENT_UPREL"."AGENT_ID" "AGENT_ID",MAX("T_LDIM_AGENT_UPREL"."REL_AGENT_ID") "MAX(REL_...
greatsql>insertintot1values(3,null);Query OK,1rowaffected(0.07sec)greatsql>select*fromt1wheret1.c2notin(selectt2.c2fromt2wheret2.c2isnotnull);+---+---+|c1|c2|+---+---+|2|b|+---+---+1rowinset(0.00sec)greatsql>select*fromt1wherenotexists(select1fromt2wheret2.c2=t1.c2)...