Question

我有两张桌子：

GererLocationAppart(IdAppartL, MatriculeEmploye)
Employe(MatriculeEmploye, PrenomEmploye, NomEmploye, NumeroTelephoneEmploye)

我想得到一张包含“PrenomEmploye”，“NomEmploye”和“Id AppartL”栏目的表格。最后一列应该具有每个“MatriculeEmploye”所指的行数。我知道我应该在

之间做一个混合

Select Distinct PrenomEmploye, NomEmploye, IdAppartL
From Employe E1, GererLocationAppart G1
Where E1.MatriculeEmploye=G1.MatriculeEmploye;

并且

SELECT MatriculeEmploye, COUNT(IdAppartL)
FROM GererLocationAppart
GROUP BY MatriculeEmploye;

但我不知道怎么做.. 我试试：

Select Distinct PrenomEmploye, NomEmploye
From Employe
Where MatriculeEmploye in
(SELECT MatriculeEmploye, COUNT(IdAppartL)
FROM GererLocationAppart
GROUP BY MatriculeEmploye);

但我明白了：

ERROR 1241 (21000): Operand should contain 1 column(s)

Answer 1

SELECT
 E1.PrenomEmploye
,E1.NomEmploye
,E1.IdAppartL
,COUNT(G1.IdAppartL) as CountMatriculeEmploye
From Employe E1
JOIN GererLocationAppart G1 ON E1.MatriculeEmploye=G1.MatriculeEmploye
GROUP BY E1.MatriculeEmploye;

Answer 2

IN之后的子查询必须只返回1列。您将返回MatriculeEmploye, COUNT(IdAppartL) 2列。您的查询应该是：

Select e.PrenomEmploye, e.NomEmploye, COUNT(g.IdAppartL)
From Employe e 
  INNER JOIN GererLocationAppart g ON g.MatriculeEmploye=e.MatriculeEmploye
GROUP BY 1,2;

请注意，此查询将合并具有相同（Prenom，Nom）对的员工，因此如果更改选择，您可能还希望将e.MatriculeEmploye添加到SELECT和GROUP BY子句（GROUP BY 1,2,3到SELECT e.MatriculeEmploye, e.Prenom, ...）。

无法建立交界和分组

2 个答案: