Question

我想将Department_name更新为deparment_name，并将'_1'（示例：Administration_1）更新为2，但这里是错误，请帮助正确书写答案。错误：单行子查询返回多行

UPDATE departments
SET department_name= (SELECT department_name || '_1' from departments)
WHERE  manager_id=
(select manager_id from  employees 
WHERE  MOD( manager_id, 2) != 0);

Answer 1

您可以尝试使用合并

MERGE INTO departments a
    USING ( SELECT department_name || '_1' as name,
            DEPARTMENT_ID from departments
            WHERE  manager_id in (
           (select manager_id from  employees 
            WHERE  MOD( manager_id, 2) != 0)
           )
         ) b
    ON ( a.DEPARTMENT_ID = b.DEPARTMENT_ID )
    WHEN MATCHED THEN 
    UPDATE SET  a.department_name = b.name

Answer 2

您正在尝试使用过多的行来更新单行（您的（从部门中选择SELECT department_name ||'_1'））我认为您可以做到

SET department_name= department_name || '_1'

Answer 3

您可以在下面尝试

UPDATE departments
SET department_name= SELECT department_name || '_1' 
WHERE  exists
     (select employees.manager_id from  employees where departments.manager_id =employees.manager_id
      and MOD( employees.manager_id, 2) != 0)

错误：单行子查询返回多个行

3 个答案: