008-LAMP_MySQL_DML

008-LAMP_MySQL_DML

DML

insert delete updata select

insert

注意：字符型需要使用引号，数值型不能使用引号

Syntax:

INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE]

[INTO] tbl_name [(col_name,…)]

{VALUES | VALUE} ({expr | DEFAULT},…),(…),…

[ ON DUPLICATE KEY UPDATE

col_name=expr

[, 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

[, col_name=expr] … ]

Or:

INSERT [LOW_PRIORITY | HIGH_PRIORITY] [IGNORE]

[INTO] tbl_name [(col_name,…)]

SELECT …

[ ON DUPLICATE KEY UPDATE

col_name=expr

[, col_name=expr] … ]

INSERT inserts new rows into an existing table. The INSERT … VALUES

and INSERT … SET forms of the statement insert rows based on

explicitly specified values. The INSERT … SELECT form inserts rows

selected from another table or tables. INSERT … SELECT is discussed

further in [HELP INSERT SELECT].

插入所有数据

MariaDB [sdb]> DESC students;
+-------+---------------------+------+-----+---------+-------+
| Field | Type                | Null | Key | Default | Extra |
+-------+---------------------+------+-----+---------+-------+
| id    | int(10) unsigned    | NO   |     | NULL    |       |
| name  | char(30)            | NO   |     | NULL    |       |
| class | varchar(100)        | NO   |     | NULL    |       |
| age   | tinyint(3) unsigned | YES  |     | NULL    |       |
| sex   | enum('F','M')       | YES  |     | NULL    |       |
+-------+---------------------+------+-----+---------+-------+
5 rows in set (0.00 sec)

MariaDB [sdb]> INSERT INTO students VALUES (201201,'husa','optimize',19,'F');
Query OK, 1 row affected (0.00 sec)

插入不完整数据

MariaDB [sdb]> INSERT INTO students (id,name,age,sex) VALUES (201202,'xizhu',120,'M');
Query OK, 1 row affected, 1 warning (0.00 sec)

MariaDB [sdb]> SELECT * FROM students;
+--------+-------+----------+------+------+
| id     | name  | class    | age  | sex  |
+--------+-------+----------+------+------+
| 201201 | husa  | optimize |   19 | F    |
| 201202 | xizhu |          |  120 | M    |
+--------+-------+----------+------+------+
2 rows in set (0.00 sec)

插入多行数据

MariaDB [sdb]> INSERT INTO students VALUES (201203,'wangzhenyi','optimize',18,'M'),(201204,'youzhu','optimize',21,'M');
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

MariaDB [sdb]> SELECT * FROM students;                                    +--------+------------+----------+------+------+
| id     | name       | class    | age  | sex  |
+--------+------------+----------+------+------+
| 201201 | husa       | optimize |   19 | F    |
| 201202 | xizhu      |          |  120 | M    |
| 201203 | wangzhenyi | optimize |   18 | M    |
| 201204 | youzhu     | optimize |   21 | M    |
+--------+------------+----------+------+------+
4 rows in set (0.00 sec)

select

Syntax:
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 [, select_expr ...]
[FROM table_references
[WHERE where_condition]
[GROUP BY {col_name | expr | position}
[ASC | DESC], ... [WITH ROLLUP]]
[HAVING where_condition]
[ORDER BY {col_name | expr | position}
[ASC | DESC], ...]
[LIMIT {[offset,] row_count | row_count OFFSET offset}]
[PROCEDURE procedure_name(argument_list)]
[INTO OUTFILE 'file_name'
[CHARACTER SET charset_name]
export_options
| INTO DUMPFILE 'file_name'
| INTO var_name [, var_name]]
[FOR UPDATE | LOCK IN SHARE MODE]]

SELECT is used to retrieve rows selected from one or more tables, and
can include UNION statements and subqueries. See [HELP UNION], and http://dev.mysql.com/doc/refman/5.5/en/subqueries.html. 
The most commonly used clauses of SELECT statements are these:

o Each select_expr indicates a column that you want to retrieve. There
must be at least one select_expr.

o table_references indicates the table or tables from which to retrieve
rows. Its syntax is described in [HELP JOIN].

o The WHERE clause, if given, indicates the condition or conditions
that rows must satisfy to be selected. where_condition is an
expression that evaluates to true for each row to be selected. The
statement selects all rows if there is no WHERE clause.

In the WHERE expression, you can use any of the functions and
operators that MySQL supports, except for aggregate (summary)
functions. See http://dev.mysql.com/doc/refman/5.5/en/expressions.html, and http://dev.mysql.com/doc/refman/5.5/en/functions.html. 
SELECT can also be used to retrieve rows computed without reference to
any table.

查询id，name并使用别名

MariaDB [sdb]> SELECT id as stuID,name FROM students;
+--------+------------+
| stuID  | name       |
+--------+------------+
| 201201 | husa       |
| 201202 | xizhu      |
| 201203 | wangzhenyi |
| 201204 | youzhu     |
+--------+------------+
4 rows in set (0.00 sec)

操作符：

=,>...
between and

or,and,not

like 'pattern'
%：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

排序
order by
ASC升序
DESC降序

\g\G横排竖排显示

从表中查询名字中包含’zh’的所有信息

MariaDB [sdb]> SELECT * FROM students WHERE name LIKE '%zh%';
+--------+------------+----------+------+------+
| id     | name       | class    | age  | sex  |
+--------+------------+----------+------+------+
| 201202 | xizhu      |          |  120 | M    |
| 201203 | wangzhenyi | optimize |   18 | M    |
| 201204 | youzhu     | optimize |   21 | M    |
+--------+------------+----------+------+------+
3 rows in set (0.00 sec)

delete

按行删除，删除的是 记录

Syntax:
Single-table syntax:

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

Multiple-table syntax:

DELETE [LOW_PRIORITY] [QUICK] [IGNORE]
tbl_name[.*] [, tbl_name[.*]] ...
FROM table_references
[WHERE where_condition]

Or:

DELETE [LOW_PRIORITY] [QUICK] [IGNORE]
FROM tbl_name[.*] [, tbl_name[.*]] ...
USING table_references
[WHERE where_condition]

For the single-table syntax, the DELETE statement deletes rows from
tbl_name and returns a count of the number of deleted rows. This count
can be obtained by calling the ROW_COUNT() function (see http://dev.mysql.com/doc/refman/5.5/en/information-functions.html). The
WHERE clause, if given, specifies the conditions that identify which
rows to delete. With no WHERE clause, all rows are deleted. If the
ORDER BY clause is specified, the rows are
8a90
deleted in the order that is
specified. The LIMIT clause places a limit on the number of rows that
can be deleted.

For the multiple-table syntax, DELETE deletes from each tbl_name the
rows that satisfy the conditions. In this case, ORDER BY and LIMIT
cannot be used.

where_condition is an expression that evaluates to true for each row to
be deleted. It is specified as described in http://dev.mysql.com/doc/refman/5.5/en/select.html. 
Currently, you cannot delete from a table and select from the same
table in a subquery.

You need the DELETE privilege on a table to delete rows from it. You
need only the SELECT privilege for any columns that are only read, such
as those named in the WHERE clause.

删除class为空的记录

MariaDB [sdb]> SELECT * FROM students;
+--------+------------+----------+------+------+
| id     | name       | class    | age  | sex  |
+--------+------------+----------+------+------+
| 201201 | husa       | optimize |   19 | F    |
| 201202 | xizhu      |          |  120 | M    |
| 201203 | wangzhenyi | optimize |   18 | M    |
| 201204 | youzhu     | optimize |   21 | M    |
| 201205 | weige      | optimize | NULL | M    |
+--------+------------+----------+------+------+
5 rows in set (0.00 sec)

MariaDB [sdb]> DELETE FROM students WHERE age IS NULL;
Query OK, 1 row affected (0.01 sec)

MariaDB [sdb]> SELECT * FROM students;
+--------+------------+----------+------+------+
| id     | name       | class    | age  | sex  |
+--------+------------+----------+------+------+
| 201201 | husa       | optimize |   19 | F    |
| 201202 | xizhu      |          |  120 | M    |
| 201203 | wangzhenyi | optimize |   18 | M    |
| 201204 | youzhu     | optimize |   21 | M    |
+--------+------------+----------+------+------+
4 rows in set (0.00 sec)

update

Syntax:
Single-table syntax:

UPDATE [LOW_PRIORITY] [IGNORE] table_reference
SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
[WHERE where_condition]
[ORDER BY ...]
[LIMIT row_count]

Multiple-table syntax:

UPDATE [LOW_PRIORITY] [IGNORE] table_references
SET col_name1={expr1|DEFAULT} [, col_name2={expr2|DEFAULT}] ...
[WHERE where_condition]

For the single-table syntax, the UPDATE statement updates columns of
existing rows in the named table with new values. The SET clause
indicates which columns to modify and the values they should be given.
Each value can be given as an expression, or the keyword DEFAULT to set
a column explicitly to its default value. The WHERE clause, if given,
specifies the conditions that identify which rows to update. With no
WHERE clause, all rows are updated. If the ORDER BY clause is
specified, the rows are updated in the order that is specified. The
LIMIT clause places a limit on the number of rows that can be updated.

将name中有zh字符的记录的age字段全部设置为20

MariaDB [sdb]> SELECT * FROM students;
+--------+------------+----------+------+------+
| id     | name       | class    | age  | sex  |
+--------+------------+----------+------+------+
| 201201 | husa       | optimize |   19 | F    |
| 201202 | xizhu      |          |  120 | M    |
| 201203 | wangzhenyi | optimize |   18 | M    |
| 201204 | youzhu     | optimize |   21 | M    |
+--------+------------+----------+------+------+
4 rows in set (0.00 sec)

MariaDB [sdb]> UPDATE students SET age=20 WHERE name LIKE '%zh%';
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3  Changed: 3  Warnings: 0

MariaDB [sdb]> SELECT * FROM students;
+--------+------------+----------+------+------+
| id     | name       | class    | age  | sex  |
+--------+------------+----------+------+------+
| 201201 | husa       | optimize |   19 | F    |
| 201202 | xizhu      |          |   20 | M    |
| 201203 | wangzhenyi | optimize |   20 | M    |
| 201204 | youzhu     | optimize |   20 | M    |
+--------+------------+----------+------+------+
4 rows in set (0.00 sec)

删除sex字段，使用alter drop而不是delete或者update

MariaDB [sdb]> SELECT * FROM students;
+--------+------------+----------+------+------+
| id     | name       | class    | age  | sex  |
+--------+------------+----------+------+------+
| 201201 | husa       | optimize |   19 | F    |
| 201202 | xizhu      |          |   20 | M    |
| 201203 | wangzhenyi | optimize |   20 | M    |
| 201204 | youzhu     | optimize |   20 | M    |
+--------+------------+----------+------+------+
4 rows in set (0.00 sec)

MariaDB [sdb]> ALTER TABLE students DROP sex;
Query OK, 4 rows affected (0.01 sec)
Records: 4  Duplicates: 0  Warnings: 0

MariaDB [sdb]> SELECT * FROM students;
+--------+------------+----------+------+
| id     | name       | class    | age  |
+--------+------------+----------+------+
| 201201 | husa       | optimize |   19 |
| 201202 | xizhu      |          |   20 |
| 201203 | wangzhenyi | optimize |   20 |
| 201204 | youzhu     | optimize |   20 |
+--------+------------+----------+------+
4 rows in set (0.00 sec)