SQL数据操作语句语法

 内容来自实验楼：MySQL 基础课程 

1. DELETE语法：
   单表语法：

   DELETE [LOW_PRIORITY] [QUICK] [IGNORE] FROM tbl_name
       [WHERE where_definition]
       [ORDER BY ...]
       [LIMIT row_count]

   多表语法：

   DELETE [LOW_PRIORITY] [QUICK] [IGNORE]
       tbl_name[.*] [, tbl_name[.*] ...]
       FROM table_references
       [WHERE where_definition]
   
   or：
   
   DELETE [LOW_PRIORITY] [QUICK] [IGNORE]
       FROM tbl_name[.*] [, tbl_name[.*] ...]
       USING table_references
       [WHERE where_definition]

   当您不想知道被删除的行的数目时，有一个更快的方法，即使用TRUNCATE TABLE。
   如果DELETE语句中含有ORDER BY子句，则按照子句中指定的顺序删除行，再结合LIMIT语句会显得非常有优势：
   DELETE FROM somelog WHERE user = 'jcole' ORDER BY timestamp_column LIMIT 1;

2. DO语法：DO expr [, expr] ...
   DO用于执行表达式，但是不返回任何结果。DO是SELECT expr的简化表达方式。

3. INSERT语法：

   INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE]
       [INTO] tbl_name [(col_name,...)]
       VALUES ({expr | DEFAULT},...),(...),...
       [ ON DUPLICATE KEY UPDATE col_name=expr, ... ]
   
   or：
   
   INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE]
       [INTO] tbl_name
       SET col_name={expr | DEFAULT}, ...
       [ ON DUPLICATE KEY UPDATE col_name=expr, ... ]
   
   or：
   
   INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE]
       [INTO] tbl_name [(col_name,...)]
       SELECT ...
       [ ON DUPLICATE KEY UPDATE col_name=expr, ... ]

   INSERT...SELECT形式的语句插入从其它表中选出的行。

4. LOAD DATA INFILE语法：

   LOAD DATA [LOW_PRIORITY | CONCURRENT] [LOCAL] INFILE 'file_name.txt'
       [REPLACE | IGNORE]
       INTO TABLE tbl_name
       [FIELDS
           [TERMINATED BY 'string']
           [[OPTIONALLY] ENCLOSED BY 'char']
           [ESCAPED BY 'char' ]
       ]
       [LINES
           [STARTING BY 'string']
           [TERMINATED BY 'string']
       ]
       [IGNORE number LINES]
       [(col_name_or_user_var,...)]
       [SET col_name = expr,...)]

    

5. REPLACE语法：

   REPLACE [LOW_PRIORITY | DELAYED]
       [INTO] tbl_name [(col_name,...)]
       VALUES ({expr | DEFAULT},...),(...),...
   
   或：
   
   REPLACE [LOW_PRIORITY | DELAYED]
       [INTO] tbl_name
       SET col_name={expr | DEFAULT}, ...
   
   或：
   
   REPLACE [LOW_PRIORITY | DELAYED]
       [INTO] tbl_name [(col_name,...)]
       SELECT ...

   REPLACE的运行模式与INSERT很相像。只有一点除外，如果表中的一个旧记录与一个用于PRIMARY KEY或一个UNIQUE索引的新记录具有相同的值，则在新记录被插入之前，旧记录被删除。

6. SELECT语法：

   SELECT
       [ALL | DISTINCT | DISTINCTROW ]
         [HIGH_PRIORITY]
         [STRAIGHT_JOIN]
         [SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]
         [SQL_CACHE | SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS]
       select_expr, ...
       [INTO OUTFILE 'file_name' export_options
         | INTO DUMPFILE 'file_name']
       [FROM table_references
       [WHERE where_definition]
       [GROUP BY {col_name | expr | position}
         [ASC | DESC], ... [WITH ROLLUP]]
       [HAVING where_definition]
       [ORDER BY {col_name | expr | position}
         [ASC | DESC] , ...]
       [LIMIT {[offset,] row_count | row_count OFFSET offset}]
       [PROCEDURE procedure_name(argument_list)]
       [FOR UPDATE | LOCK IN SHARE MODE]]

   可以在没有表可以参考的情况下指定DUAL为一个虚拟的表名：SELECT 1 + 1 FROM DUAL;
   (1).JOIN语法：

   table_reference:
       table_factor
     | join_table
   
   table_factor:
       tbl_name [[AS] alias]
           [{USE|IGNORE|FORCE} INDEX (key_list)]
     | ( table_references )
     | { OJ table_reference LEFT OUTER JOIN table_reference
           ON conditional_expr }
   
   join_table:
       table_reference [INNER | CROSS] JOIN table_factor [join_condition]
     | table_reference STRAIGHT_JOIN table_factor
     | table_reference STRAIGHT_JOIN table_factor ON condition
     | table_reference LEFT [OUTER] JOIN table_reference join_condition
     | table_reference NATURAL [LEFT [OUTER]] JOIN table_factor
     | table_reference RIGHT [OUTER] JOIN table_reference join_condition
     | table_reference NATURAL [RIGHT [OUTER]] JOIN table_factor
   
   join_condition:
       ON conditional_expr
     | USING (column_list)

   (2).UNION语法：

   SELECT ...
   UNION [ALL | DISTINCT]
   SELECT ...

    

7. UPDATE语法：
   单表：

   UPDATE [LOW_PRIORITY] [IGNORE] tbl_name
       SET col_name1=expr1 [, col_name2=expr2 ...]
       [WHERE where_definition]
       [ORDER BY ...]
       [LIMIT row_count]

   多表：

   UPDATE [LOW_PRIORITY] [IGNORE] table_references
       SET col_name1=expr1 [, col_name2=expr2 ...]
       [WHERE where_definition]