mysql学习笔记(6-DML命令)

DML：INSERT， DELETE， UPDATE， SELECT

INSERT INTO：

INSERT [INTO] tbl_name [(col1,...)] {VALUES|VALUE} (val1, ...),(...),...

注意：

字符型：引号；

数值型：不能用引号；

SELECT：

(1) SELECT * FROM tbl_name;

(2) SELECT col1, col2, ... FROM tbl_name;

显示时，字段可以显示为别名；

col_name AS col_alias

(3) SELECT col1, ... FROM tbl_name WHERE clause;

WHERE clause：用于指明挑选条件；

col_name 操作符 value：

age > 30;

操作符(1) ：

>, <, >=, <=, ==, !=

组合条件：

and

or

not

操作符(2) ：

BETWEEN ... AND ...

LIKE 'PATTERN'

通配符：

%：任意长度的任意字符；

_：任意单个字符；

RLIKE 'PATTERN'

正则表达式对字符串做模式匹配；

IS NULL

IS NOT NULL

(4) SELECT col1, ... FROM tbl_name [WHERE clause] ORDER BY col_name, col_name2, ... [ASC|DESC];

ASC: 升序；

DESC： 降序；

DELETE：

DELETE FROM tbl_name [WHERE where_condition] [ORDER BY ...] [LIMIT row_count] (1) DELETE FROM tbl_name WHERE where_condition

(2) DELETE FROM tbl_name [ORDER BY ...] [LIMIT row_count]

UPDATE：

UPDATE [LOW_PRIORITY] [IGNORE] table_reference SET col_name1=value1 [, col_name2=value2] ... [WHERE where_condition] [ORDER BY ...] [LIMIT row_count]