sql join与 top 一起使用 select top 10 * From A outer apply (select top 1 * from B where A.ID=B.ID order by A.DATETIME desc) as B 关键 处( outer apply )
select top 10 * From A outer apply (select top 1 * from B where A.ID=B.ID order by A.DATETIME desc) as B 关键 处( outer apply )
不知道理解是否正确,使用inner join 如果未指定排序, 数据库会自动选择最优的排序来排,比如上面的结果, 当top 1 top 2的时候,数据量小,所以直接返回的是根据id排序的结果, 当top 3的时候数据库认为先根据brandid来排序,再根据产品id更优,所以排序就变了 当使用top N, N数字比brandid=1的数量大时候,top N...
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...
create table t1 (id int,score int,sex int)create table t2 (id1 int,id2 int,dscore int)insert into t1 values (1,5,1)insert into t1 values (2,4,0)insert into t1 values (3,7,1)insert into t2 values (1,2,1)insert into t2 values (2,3,2)...
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？
首先,依據Row_Number的方式,依據時間排序之後給予編號,並且給予【編號減1】的來做為比對JOIN的Key 請參考以下這篇來設計Row_Number https://dotblogs.com.tw/topcat/2009/08/06/9906 因此就是這樣的語法來處理 prettyprint複製 SELECT ROW_NUMBER() OVER(ORDER BY DTime) AS ROWID ...
(8)SELECT(9)DISTINCT(11)<TOP_specification>(1)FROM<left_table>(3)<join_type>JOIN<right_table>(2)ON<join_condition>(4)WHERE<where_condition>(5)GROUPBY<group_by_list>(6)WITH{CUBE|ROLLUP}(7)HAVING<having_condition>(10)ORDERBY<order_by_list> 细心的读者可能...
Cross join Note For more information on join syntax, see FROM clause plus JOIN, APPLY, PIVOT (Transact-SQL). SQL Server employs four types of physical join operations to carry out the logical join operations: Nested Loops joins Merge joins Hash joins Adaptive joins (starting with SQL Server ...
INNER JOIN –An INNER JOIN is used to return records of the same value in two tables. LEFT JOIN –LEFT JOIN is used to join all the rows in the left table with matching rows in the right table. RIGHT JOIN –RIGHT JOIN is used to join all the rows in the right table with the cor...