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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]

    

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mysql学习笔记(6-DML命令)