为什么要在 SQL 中使用 WHERE 1=0 语句

# 使用 WHERE 1=0 语句的原因及案例代码

sql
SELECT * FROM employees WHERE department = 'IT';

sql
SELECT * FROM table_name WHERE 1=0;

sql
-- 创建一个包含员工信息的临时表
CREATE TEMPORARY TABLE temp_employees AS
SELECT * FROM employees WHERE 1=0;
-- 定义变量来存储动态条件
DECLARE @department NVARCHAR(50) = 'IT';
-- 根据用户输入动态构建查询条件
IF @department IS NOT NULL
BEGIN
    INSERT INTO temp_employees
    SELECT * FROM employees WHERE department = @department;
END;
-- 查询最终结果
SELECT * FROM temp_employees;