IN 操作符
下面的 SQL 语句选取 name 为 "G" 或 "h" 的所有记录:
SELECT * FROM table
WHERE name IN ('G','h');
WHERE name IN ('G','h');
IN 与 = 的异同
- 相同点:均在WHERE中使用作为筛选条件之一、均是等于的含义
- 不同点:IN可以规定多个值,等于规定一个值
IN
SELECT column_name(s)
FROM table_name
WHERE column_name IN (value1,value2,...);
=
SELECT column_name(s) FROM table_name WHERE column_name=value1;
in 与 = 的转换
select * from Websites where name in ('Goo','g');
可以转换成 = 的表达:
select * from Websites where name='Google' or name='g';