SELECT top 1 l_title.l_id,l_title.bigclass,l_title.name,l_title.title,l_title.click,l_title.addtime, (select top 1 h_hf.addtime from h_hf where l_id=l_title.l_id order by h_hf.addtime desc,h_hf.l_id) as h_hfaddtime, (select top 1 h_hf.l_idfrom h_hf w...
(select TOP(1) * from b表 WHERE [Name] = a.[AName] ORDER BY BNo desc) b 总结: 1. 理解 CROSS APPLY 与 OUTER APPLY(个人理解) 1) CROSS APPLY 的意思是“交叉应用”,在查询时首先查询左表,然后右表的每一条记录跟左表的当前记录进行匹配。匹配成功则将左表与右表的记录合并为一条记录输出;...
select * from ainner joinb on a.aid = b.bid这是仅取出匹配的数据. 此时的取出的是: 1 a1 b1 2 a2 b2 那么left join 指: select * from aleft joinb on a.aid = b.bid 首先取出a表中所有数据,然后再加上与a,b匹配的的数据 此时的取出的是: 1 a1 b1 2 a2 b2 3 a3 空字符 同样的也有...
left join tableB as b on ***.tid = ***.tid group by ***.tid order by ***.tid. 扩展资料: LEFT JOIN 关键字会从左表 (table_name1) 那里返回所有的行,即使在右表 (table_name2) 中没有匹配的行。 LEFT JOIN 关键字语法 SELECT column_name(s) FROM table_name1 LEFT JOIN table_name2...
This scenario doesn't come up too often, but the other day I had a requirement to do a left join through a one to many relationship but only get 1 result from the right side of the join. This kind of scenario can often be accomplished using sub selects, but in this case I needed...
1、子查询出现在where子句中 1、查询⼯资⼤于10号部⻔的平均⼯资的⾮10号部⻔的员⼯信息 分析: 1)10号部⻔的平均⼯资 select avg(sal) from emp where deptno = 10; 2)查询员工信息 select * from emp where deptno != 10 and sal > (select avg(sal) from emp where deptno = 10...
select a.nid,a.name,max(b.price) from a left join b on a.nid =b.nid group by a.nid,a.name是这样吗？
<join_type> JOIN <right_table> ON <join_condition> WHERE <where_condition> GROUP BY <group_by_list> HAVING <having_condition> ORDER BY <order_by_condition> LIMIT <limit_number> 1. 2. 3. 4. 5. 6. 7. 8. 9. View Code 二SELECT语句关键字的执行顺序 ...
LEFT JOIN与多个SELECT语句 作为一个云计算领域的专家,我可以告诉你,LEFT JOIN 和多个 SELECT 语句是 SQL 查询中的关键概念。 LEFT JOIN 是一种连接两个表的方法,它会返回左表中的所有记录,即使右表中没有匹配的记录。如果右表中没有匹配的记录,则结果集中的该行右表的字段将为 NULL。 多个SELECT 语句可以在...
select * from T1 left join T2 on T2.id=T1.id;SQL LEFT JOIN 关键字 LEFT JOIN 关键字会从左表 (table_name1) 那里返回所有的行，即使在右表 (table_name2) 中没有匹配的行。LEFT JOIN 关键字语法 SELECT column_name(s)FROM table_name1 LEFT JOIN table_name2 ON table_name1....