select a.teacherId,a.teacherName,b.salary from tb1 a left join tb2 b on a.teacherId=b.teacherId
WITH a1 (teacherId,teacherName) AS ( SELECT 1,'王老师' UNION ALL SELECT 2,'李老师' UNION ALL SELECT 3,'赵老师' ) ,a2 (Id,teacherId,salary) AS ( SELECT 1,1,'2000' UNION ALL SELECT 2,3,'2500' ) SELECT *,(SELECT salary FROM a2 WHERE teacherId=a.teacherId) salary FROM a1 a
from tb1 a
left join tb2 b on a.teacherId=b.teacherId
WITH a1 (teacherId,teacherName) AS
(
SELECT 1,'王老师' UNION ALL
SELECT 2,'李老师' UNION ALL
SELECT 3,'赵老师'
)
,a2 (Id,teacherId,salary) AS
(
SELECT 1,1,'2000' UNION ALL
SELECT 2,3,'2500'
)
SELECT *,(SELECT salary FROM a2 WHERE teacherId=a.teacherId) salary
FROM a1 a