MySQL中有很多不同的條件運(yùn)算符,這些運(yùn)算符對于選擇和過濾數(shù)據(jù)非常有用。以下是一些常用的條件運(yùn)算符:
= :等于 != 或<>:不等于 >:大于< :小于 >= :大于等于<= :小于等于 BETWEEN :在一個范圍內(nèi) IN :指定某個范圍內(nèi)的值 NOT :否定
等于操作符是最常見的運(yùn)算符之一,可以用來過濾數(shù)據(jù)中某個列等于特定值的行,例如:
SELECT * FROM employees WHERE department = 'Sales';
不等于操作符可以用來選擇數(shù)據(jù)中某個列不等于特定值的行:
SELECT * FROM employees WHERE department != 'Sales';
大于和小于操作符用于選擇列中大于或小于特定值的行:
SELECT * FROM employees WHERE salary >50000; SELECT * FROM employees WHERE age< 30;
大于等于和小于等于操作符可以用于選擇等于或大于/小于特定值的行:
SELECT * FROM employees WHERE salary >= 50000; SELECT * FROM employees WHERE age<= 30;
BETWEEN操作符用于選擇某個范圍內(nèi)的值,例如:
SELECT * FROM employees WHERE age BETWEEN 25 AND 40;
IN操作符可以用于選擇某個范圍內(nèi)的值,例如:
SELECT * FROM employees WHERE department IN ('Sales', 'Marketing');
NOT操作符可以用于否定一個條件,例如:
SELECT * FROM employees WHERE NOT department = 'Sales';
以上就是一些常用的MySQL條件運(yùn)算符,這些運(yùn)算符可以根據(jù)需要自由組合以過濾數(shù)據(jù)和檢索所需的結(jié)果。