QL> CREATE TABLE t1 AS SELECT ROWNUM ID FROM dual CONNECT BY ROWNUM<=10; Table created SQL> ...
var haveChange from newScore in newScoreList join oldScore in oldScoreList on new newScore.ExamId,newScore.StudentId,newScore.Subject,newScore.ClassId equals new oldScore.ExamId,oldScore.StudentId,old ...
2014-05-06 15:25 0 20403 推荐指数:
QL> CREATE TABLE t1 AS SELECT ROWNUM ID FROM dual CONNECT BY ROWNUM<=10; Table created SQL> ...
Sql 查询语句应用左连接时的链接条件中经常加一些常量值在里面如: “On a.id= b.id and b.is_del =0 and b.is_old =1” 这种条件如果加在表与表之间连接后的where条件中时有什么不一样呢? 答:其实仔细想想我们都能想到,左连接的目的是要取左边的所有 ...
Sql 查询语句应用左连接时的链接条件中经常加一些常量值在里面如: “On a.id= b.id and b.is_del =0 and b.is_old =1” 这种条件如果加在表与表之间连接后的where条件中时有什么不一样呢? 答:其实仔细想想我们都能想到,左连接的目的是要取左边的所有 ...
l = (from a in list join b in db.tb_e_community_building_unit_room_owner on a.RoomOwnerID equals b.OwnerID where b.OwnerName.Contains(tn ...
join on 与 where 条件的执行先后顺序: join on 条件先执行,where条件后执行;join on的条件在连接表时过滤,而where则是在生成中间表后对临时表过滤 left join、right join、full join、inner join区别 ...
var tmp = from a in DT1.AsEnumerable() join b in DT2.AsEnumerable() on new { bm = a.Field<string>("编码"), lx = "类型" } equals new { bm ...
1、sql语句: 2、linq写法: 1)、方法一: 将多个字段的比较,new 一个对象进行比较; 注意:对象的属性名要保持一致; 2)、方法二: ...
所以linq为什么要这么写,看到生成的sql语句 就不言而喻了,因为linq多管闲事的将NULL给总结进去了 ...