SELECT
TOP 10 pcchrgcod
FROM (
SELECT TOP 10 acctno AS pcchrgcod FROM hdocord
WHERE acctno LIKE '2007-000%'
GROUP BY
acctno
UNION
SELECT TOP 10 acctno AS pcchrgcod FROM hpatchrg
WHERE acctno
我写了一个查询，旨在返回用户事务之间的分钟数。 MS Access需要10分钟来运行它，我无法使用结果。我怎样才能提高其表现？ SELECT TestDataset.ID, TestDataset.OperatorID, TestDataset.DTCreated,
(SELECT TOP 1 t2.DtCreated
FROM TestDataSet as t2
select name from myschema.table1 where
COL1 = 'A'and
COL2= 'B' and
LEVEL = (select max(LEVEL) from myschema.table1 where USERTYPE='C')
我知道我对查询表中的最高水平，而不是与用户类型“C”行中的最大电平选择一列的最大值。我只需要针对那个usertype进行
如何将以下内容写入连接并获取相同数量的行？ SELECT
s.subjectid,
s.subjectname,
(SELECT
COUNT(*)
FROM dbo.Classes AS c
WHERE c.SubjectID = s.SubjectID
AND c.MondaySchedule = 1)
AS num
我的任务问题：显示每个客户的贷款总数，包括没有贷款的客户。提示：首先使用子查询形成外部连接表的右侧部分。 我已经用下面的代码来实现这一点： SELECT DISTINCT
C.CustomerID,
C.LastName,
C.FirstName,
COUNT(L.LoanID) AS 'Number of Loans'
FROM Customer C
下面的子查询返回一组值的最小值（S）： SELECT R.mID AS MID, AVG(R.stars) AS AVGSTARS FROM Rating R
GROUP BY R.mID
ORDER BY AVGRSTARS
返回下列值： MID AVGSTARS
104 2.5000
103 2.5000
101 3.0000
108 3.3333
107 4.0000
加入我写了2个查询一个是子查询 SELECT DISTINCT pp.employeeid
FROM payment pp JOIN Employee e
ON e.employeeid = pp.employeeid WHERE pp.employeeid IN
(SELECT employeeid
FROM employee
WHERE branchid IN
(SELECT br