WHERE

SELECT column01[, column02, column03...] FROM table_name WHERE condition;

WHERE与ORDER BY配合的时候，order by在where后面。

比较符

WHERE中的条件，有很多比较符，可提的就是!=与<>是一个意思，表示不等于。

BETWEEN AND

WHERE column_name BETWEEN start AND end;

WHERE column_name >= start and column_name <=end; --这俩等价

检查为空

WHERE column_name IS NULL; --- IS NOT NULL

WHERE AND / WHERE OR

WHERE AND优先级比WHERE OR高，结合使用有顺序要求的，使用括号。

即

WHERE condition01 OR condition02 AND condition03;

-- 与

WHERE condition01 OR (condition02 AND condition03); -- 是等价的。AND优先级比OR要高。

WHERE IN

其实就是简写的OR

例如：

WHERE price in(10, 11, 4); 

NOT

WHERE NOT condition; -- 否定条件

NOT IN(...);

NOT BETWEEN AND;

NOT EXISTS;

LIKE

WHERE name LIKE '%z_'; --%表示n个字符，_表示一个字符