SQL 查询

SQL 查询

SQL SELECT

SELECT column1, column2, ... FROM table_name; * 代表全部列名 [推荐] 分别列出查询列名

SQL DISTINCT[去重复]

SELECT DISTINCT column1, column2, ... FROM table_name; [注意]仅返回不同的数据行，相同行数据只显示一行

SQL WHERE[带子句]

SELECT column1, column2, ... FROM table_name WHERE condition; [子句]

= 等于

<> 不等于 [!=]

\> 大于

< 小于

\>= 大于等于

<=小于等于

BETWEEN范围

LIKE 相似

IN ()内容

SQL AND & OR [运算符]

SELECT column1, column2, ... FROM table_name WHERE condition1 AND condition2 OR condition3 NOT condition4 ...; [运算符]为真 执行返回，为假 执行跳过忽略

SQL ORDER BY[按关键字排序]

SELECT column1, column2, ... FROM table_name ORDER BY column1, column2, ... ASC|DESC; [备注] ORDER BY 关键字用于按升序或降序对结果集进行排序。 ORDER BY 关键字默认情况下按升序排序记录。