select name, designation, salary
from employee
where employeeID = 123
如果employeeID 123不存在,则sql应返回“EmployeeID无效”。
我尝试了Union和case语句,但我没有得到所需的结果。
数据库:SQL Server
这实际上必须在应用程序级而不是SQL上完成,但您可以使用NOT EXISTS
验证它:
IF NOT EXISTS (SELECT 1 FROM employee WHERE employeeID = 123)
BEGIN
PRINT 'EmployeeID is not valid' --- OR USE RETURN
-- SELECT 'EmployeeID is not valid' --- OR SELECT statement with message
END
ELSE
BEGIN
SELECT name, designation, salary
FROM employee
WHERE employeeID = 123
END