一
if(a<>"")
假如a不等于空字符串,这句SQL语句该怎么写?二
我有三个表
KJ表
KJID
TeacherID
..........................................................
Teacher表TeacherID
TeacherName
CollageID
.........................................................Collage表CollageID
CollageName我想写一个SQL语句,查询所有的KJ,根据KJ的TeacherID查到TeacherName,同时根据TeacherID查到Teacher,Teacher的CollageID查到Collage,最后生成的数据集里KJ的属性里除了本身的KJName以外,还想加上TeacherName,CollageName。
SQL语句该怎么写??
谢谢大家,希望能指点一下。
if(a<>"")
假如a不等于空字符串,这句SQL语句该怎么写?二
我有三个表
KJ表
KJID
TeacherID
..........................................................
Teacher表TeacherID
TeacherName
CollageID
.........................................................Collage表CollageID
CollageName我想写一个SQL语句,查询所有的KJ,根据KJ的TeacherID查到TeacherName,同时根据TeacherID查到Teacher,Teacher的CollageID查到Collage,最后生成的数据集里KJ的属性里除了本身的KJName以外,还想加上TeacherName,CollageName。
SQL语句该怎么写??
谢谢大家,希望能指点一下。
if a is not null
BEGIN
……
END2. SELECT T1.KJName, T2.TeacherName, T3.CollageName
FROM KJ T1
LEFT JOIN Teacher T2 ON T2.TeacherID=T1.TeacherID
LEFT JOIN Collage T3 ON T3.CollageID=T2.CollageID