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Mysql的数据查询操作

Mysql的数据查询操作

作者: A04 | 来源:发表于2018-04-23 22:57 被阅读0次

    创建一张数据表并插入数据，作为例子

    mysql> CREATE TABLE fruits
    -> (
    -> f_id    char(10)     NOT NULL,
    -> s_id    INT        NOT NULL,
    -> f_name  char(255)  NOT NULL,
    -> f_price decimal(8,2)  NOT NULL,
    -> PRIMARY KEY(f_id)
    -> );
Query OK, 0 rows affected (0.39 sec)

mysql>
mysql> INSERT INTO fruits (f_id, s_id, f_name, f_price)
    ->      VALUES('a1', 101,'apple',5.2),
    ->      ('b1',101,'blackberry', 10.2),
    ->      ('bs1',102,'orange', 11.2),
    ->      ('bs2',105,'melon',8.2),
    ->      ('t1',102,'banana', 10.3),
    ->      ('t2',102,'grape', 5.3),
    ->      ('o2',103,'coconut', 9.2),
    ->      ('c0',101,'cherry', 3.2),
    ->      ('a2',103, 'apricot',2.2),
    ->      ('l2',104,'lemon', 6.4),
    ->      ('b2',104,'berry', 7.6),
    ->      ('m1',106,'mango', 15.6),
    ->      ('m2',105,'xbabay', 2.6),
    ->      ('t4',107,'xbababa', 3.6),
    ->      ('m3',105,'xxtt', 11.6),
    ->      ('b5',107,'xxxx', 3.6);
Query OK, 16 rows affected (0.09 sec)
Records: 16  Duplicates: 0  Warnings: 0

mysql>

    1. 查询所有字段

    mysql> select * from fruits;
+------+------+------------+---------+
| f_id | s_id | f_name     | f_price |
+------+------+------------+---------+
| a1   |  101 | apple      |    5.20 |
| a2   |  103 | apricot    |    2.20 |
| b1   |  101 | blackberry |   10.20 |
| b2   |  104 | berry      |    7.60 |
| b5   |  107 | xxxx       |    3.60 |
| bs1  |  102 | orange     |   11.20 |
| bs2  |  105 | melon      |    8.20 |
| c0   |  101 | cherry     |    3.20 |
| l2   |  104 | lemon      |    6.40 |
| m1   |  106 | mango      |   15.60 |
| m2   |  105 | xbabay     |    2.60 |
| m3   |  105 | xxtt       |   11.60 |
| o2   |  103 | coconut    |    9.20 |
| t1   |  102 | banana     |   10.30 |
| t2   |  102 | grape      |    5.30 |
| t4   |  107 | xbababa    |    3.60 |
+------+------+------------+---------+
16 rows in set (0.00 sec)

mysql>

    2. 查询指定字段

    mysql> select f_id,f_name from fruits;
+------+------------+
| f_id | f_name     |
+------+------------+
| a1   | apple      |
| a2   | apricot    |
| b1   | blackberry |
| b2   | berry      |
| b5   | xxxx       |
| bs1  | orange     |
| bs2  | melon      |
| c0   | cherry     |
| l2   | lemon      |
| m1   | mango      |
| m2   | xbabay     |
| m3   | xxtt       |
| o2   | coconut    |
| t1   | banana     |
| t2   | grape      |
| t4   | xbababa    |
+------+------------+
16 rows in set (0.00 sec)

mysql>

    3. 查询指定记录

    mysql> SELECT f_name, f_price
   -> FROM fruits
   -> WHERE f_price = 10.2;
+------------+---------+
| f_name     | f_price |
+------------+---------+
| blackberry |   10.20 |
+------------+---------+
1 row in set (0.03 sec)

mysql>
mysql> SELECT f_name, f_price
   -> FROM fruits
   -> WHERE f_name = 'apple';
+--------+---------+
| f_name | f_price |
+--------+---------+
| apple  |    5.20 |
+--------+---------+
1 row in set (0.00 sec)

mysql> SELECT f_name, f_price FROM fruits WHERE f_price < 10;
+---------+---------+
| f_name  | f_price |
+---------+---------+
| apple   |    5.20 |
| apricot |    2.20 |
| berry   |    7.60 |
| xxxx    |    3.60 |
| melon   |    8.20 |
| cherry  |    3.20 |
| lemon   |    6.40 |
| xbabay  |    2.60 |
| coconut |    9.20 |
| grape   |    5.30 |
| xbababa |    3.60 |
+---------+---------+
11 rows in set (0.00 sec)

mysql>

    4. 带IN关键字的查询

    mysql> SELECT s_id,f_name, f_price
   -> FROM fruits
   -> WHERE s_id NOT IN (101,102)
   -> ORDER BY f_name;
+------+---------+---------+
| s_id | f_name  | f_price |
+------+---------+---------+
|  103 | apricot |    2.20 |
|  104 | berry   |    7.60 |
|  103 | coconut |    9.20 |
|  104 | lemon   |    6.40 |
|  106 | mango   |   15.60 |
|  105 | melon   |    8.20 |
|  107 | xbababa |    3.60 |
|  105 | xbabay  |    2.60 |
|  105 | xxtt    |   11.60 |
|  107 | xxxx    |    3.60 |
+------+---------+---------+
10 rows in set (0.00 sec)

mysql>

    5. 带BETWEEN AND的范围查询

    mysql> SELECT f_name, f_price
   -> FROM fruits
   -> WHERE f_price BETWEEN 2.00 AND 10.20;
+------------+---------+
| f_name     | f_price |
+------------+---------+
| apple      |    5.20 |
| apricot    |    2.20 |
| blackberry |   10.20 |
| berry      |    7.60 |
| xxxx       |    3.60 |
| melon      |    8.20 |
| cherry     |    3.20 |
| lemon      |    6.40 |
| xbabay     |    2.60 |
| coconut    |    9.20 |
| grape      |    5.30 |
| xbababa    |    3.60 |
+------------+---------+
12 rows in set (0.00 sec)

mysql> SELECT f_name, f_price
   -> FROM fruits
   -> WHERE f_price NOT BETWEEN 2.00 AND 10.20;
+--------+---------+
| f_name | f_price |
+--------+---------+
| orange |   11.20 |
| mango  |   15.60 |
| xxtt   |   11.60 |
| banana |   10.30 |
+--------+---------+
4 rows in set (0.00 sec)

mysql>

    6. 带LIKE的字符匹配查询

    百分号通配符（%）
mysql> SELECT f_id, f_name FROM fruits WHERE f_name LIKE 'b%';
+------+------------+
| f_id | f_name     |
+------+------------+
| b1   | blackberry |
| b2   | berry      |
| t1   | banana     |
+------+------------+
3 rows in set (0.00 sec)

mysql> SELECT f_id, f_name FROM fruits WHERE f_name LIKE '%g%';
+------+--------+
| f_id | f_name |
+------+--------+
| bs1  | orange |
| m1   | mango  |
| t2   | grape  |
+------+--------+
3 rows in set (0.00 sec)

mysql> SELECT f_name FROM fruits WHERE f_name LIKE 'b%y';
+------------+
| f_name     |
+------------+
| blackberry |
| berry      |
+------------+
2 rows in set (0.00 sec)

    下划线通配符（_）
mysql> SELECT f_id,f_name FROM fruits WHERE f_name LIKE '____y';
+------+--------+
| f_id | f_name |
+------+--------+
| b2   | berry  |
+------+--------+
1 row in set (0.00 sec)

mysql>

    创建另一张数据表并插入数据，作为例子

    mysql> CREATE TABLE customers
    -> (
    ->   c_id      int       NOT NULL AUTO_INCREMENT,
    ->   c_name    char(50)  NOT NULL,
    ->   c_address char(50)  NULL,
    ->   c_city    char(50)  NULL,
    ->   c_zip     char(10)  NULL,
    ->   c_contact char(50)  NULL,
    ->   c_email   char(255) NULL,
    ->   PRIMARY KEY (c_id)
    -> );
Query OK, 0 rows affected (0.24 sec)

mysql> INSERT INTO customers(c_id, c_name, c_address, c_city,
    -> c_zip,  c_contact, c_email)
    -> VALUES(10001, 'RedHook', '200 Street ', 'Tianjin',
    ->  '300000',  'LiMing', 'LMing@163.com'),
    -> (10002, 'Stars', '333 Fromage Lane',
    ->  'Dalian', '116000',  'Zhangbo','Jerry@hotmail.com'),
    -> (10003, 'Netbhood', '1 Sunny Place', 'Qingdao',  '266000',
    ->  'LuoCong', NULL),
    -> (10004, 'JOTO', '829 Riverside Drive', 'Haikou',
    ->  '570000',  'YangShan', 'sam@hotmail.com');
Query OK, 4 rows affected (0.09 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql>

    7. 查询空值

    mysql> SELECT c_id, c_name,c_email FROM customers WHERE c_email IS NULL;
+-------+----------+---------+
| c_id  | c_name   | c_email |
+-------+----------+---------+
| 10003 | Netbhood | NULL    |
+-------+----------+---------+
1 row in set (0.00 sec)

mysql> SELECT c_id, c_name,c_email FROM customers WHERE c_email IS NOT NULL;
+-------+---------+-------------------+
| c_id  | c_name  | c_email           |
+-------+---------+-------------------+
| 10001 | RedHook | LMing@163.com     |
| 10002 | Stars   | Jerry@hotmail.com |
| 10004 | JOTO    | sam@hotmail.com   |
+-------+---------+-------------------+
3 rows in set (0.00 sec)

mysql>

    8. 带AND的多条件查询

    mysql> SELECT s_id, f_price, f_name FROM fruits WHERE s_id = '101' AND f_price >=5;
+------+---------+------------+
| s_id | f_price | f_name     |
+------+---------+------------+
|  101 |    5.20 | apple      |
|  101 |   10.20 | blackberry |
+------+---------+------------+
2 rows in set (0.00 sec)

mysql> SELECT f_id, f_price, f_name FROM fruits
   -> WHERE s_id IN('101', '102') AND f_price >= 5 AND f_name = 'apple';
+------+---------+--------+
| f_id | f_price | f_name |
+------+---------+--------+
| a1   |    5.20 | apple  |
+------+---------+--------+
1 row in set (0.00 sec)

mysql>

    8. 带OR的多条件查询

    mysql> SELECT s_id,f_name, f_price FROM fruits WHERE s_id = 101 OR s_id = 102;
+------+------------+---------+
| s_id | f_name     | f_price |
+------+------------+---------+
|  101 | apple      |    5.20 |
|  101 | blackberry |   10.20 |
|  102 | orange     |   11.20 |
|  101 | cherry     |    3.20 |
|  102 | banana     |   10.30 |
|  102 | grape      |    5.30 |
+------+------------+---------+
6 rows in set (0.00 sec)

mysql> SELECT s_id,f_name, f_price FROM fruits WHERE s_id IN(101,102);
+------+------------+---------+
| s_id | f_name     | f_price |
+------+------------+---------+
|  101 | apple      |    5.20 |
|  101 | blackberry |   10.20 |
|  102 | orange     |   11.20 |
|  101 | cherry     |    3.20 |
|  102 | banana     |   10.30 |
|  102 | grape      |    5.30 |
+------+------------+---------+
6 rows in set (0.00 sec)

mysql>

    9. 查询结果不重复

    mysql> SELECT DISTINCT s_id FROM fruits;
+------+
| s_id |
+------+
|  101 |
|  103 |
|  104 |
|  107 |
|  102 |
|  105 |
|  106 |
+------+
7 rows in set (0.00 sec)

mysql>

    10. 对查询结果排序

    单列排序
mysql> SELECT f_name, f_price FROM fruits ORDER BY f_name;
+------------+---------+
| f_name     | f_price |
+------------+---------+
| apple      |    5.20 |
| apricot    |    2.20 |
| banana     |   10.30 |
| berry      |    7.60 |
| blackberry |   10.20 |
| cherry     |    3.20 |
| coconut    |    9.20 |
| grape      |    5.30 |
| lemon      |    6.40 |
| mango      |   15.60 |
| melon      |    8.20 |
| orange     |   11.20 |
| xbababa    |    3.60 |
| xbabay     |    2.60 |
| xxtt       |   11.60 |
| xxxx       |    3.60 |
+------------+---------+
16 rows in set (0.00 sec)

mysql>

    多列排序
mysql>SELECT f_name, f_price FROM fruits ORDER BY f_name, f_price;
+------------+---------+
| f_name     | f_price |
+------------+---------+
| apple      |    5.20 |
| apricot    |    2.20 |
| banana     |   10.30 |
| berry      |    7.60 |
| blackberry |   10.20 |
| cherry     |    3.20 |
| coconut    |    9.20 |
| grape      |    5.30 |
| lemon      |    6.40 |
| mango      |   15.60 |
| melon      |    8.20 |
| orange     |   11.20 |
| xbababa    |    3.60 |
| xbabay     |    2.60 |
| xxtt       |   11.60 |
| xxxx       |    3.60 |
+------------+---------+
16 rows in set (0.00 sec)

mysql>

    指定排序方向
mysql> SELECT f_name, f_price FROM fruits ORDER BY f_price DESC;
+------------+---------+
| f_name     | f_price |
+------------+---------+
| mango      |   15.60 |
| xxtt       |   11.60 |
| orange     |   11.20 |
| banana     |   10.30 |
| blackberry |   10.20 |
| coconut    |    9.20 |
| melon      |    8.20 |
| berry      |    7.60 |
| lemon      |    6.40 |
| grape      |    5.30 |
| apple      |    5.20 |
| xxxx       |    3.60 |
| xbababa    |    3.60 |
| cherry     |    3.20 |
| xbabay     |    2.60 |
| apricot    |    2.20 |
+------------+---------+
16 rows in set (0.00 sec)

mysql> SELECT f_price, f_name FROM fruits ORDER BY f_price DESC, f_name;
+---------+------------+
| f_price | f_name     |
+---------+------------+
|   15.60 | mango      |
|   11.60 | xxtt       |
|   11.20 | orange     |
|   10.30 | banana     |
|   10.20 | blackberry |
|    9.20 | coconut    |
|    8.20 | melon      |
|    7.60 | berry      |
|    6.40 | lemon      |
|    5.30 | grape      |
|    5.20 | apple      |
|    3.60 | xbababa    |
|    3.60 | xxxx       |
|    3.20 | cherry     |
|    2.60 | xbabay     |
|    2.20 | apricot    |
+---------+------------+
16 rows in set (0.00 sec)

mysql>

    11. 分组查询

    创建分组
mysql> SELECT s_id, COUNT(*) AS Total FROM fruits GROUP BY s_id;
+------+-------+
| s_id | Total |
+------+-------+
|  101 |     3 |
|  102 |     3 |
|  103 |     2 |
|  104 |     2 |
|  105 |     3 |
|  106 |     1 |
|  107 |     2 |
+------+-------+
7 rows in set (0.00 sec)

mysql> SELECT s_id, GROUP_CONCAT(f_name) AS Names FROM fruits GROUP BY s_id;
+------+-------------------------+
| s_id | Names                   |
+------+-------------------------+
|  101 | apple,blackberry,cherry |
|  102 | orange,banana,grape     |
|  103 | apricot,coconut         |
|  104 | berry,lemon             |
|  105 | melon,xbabay,xxtt       |
|  106 | mango                   |
|  107 | xxxx,xbababa            |
+------+-------------------------+
7 rows in set (0.00 sec)

mysql>

    使用HAVING过滤分组
mysql> SELECT s_id, GROUP_CONCAT(f_name) AS Names
    -> FROM fruits
    -> GROUP BY s_id HAVING COUNT(f_name) > 1;
+------+-------------------------+
| s_id | Names                   |
+------+-------------------------+
|  101 | apple,blackberry,cherry |
|  102 | orange,banana,grape     |
|  103 | apricot,coconut         |
|  104 | berry,lemon             |
|  105 | melon,xbabay,xxtt       |
|  107 | xxxx,xbababa            |
+------+-------------------------+
6 rows in set (0.00 sec)

mysql>

    在GROUP BY子句中使用WITH ROLLUP
mysql> SELECT s_id, COUNT(*) AS Total
    -> FROM fruits
    -> GROUP BY s_id WITH ROLLUP;
+------+-------+
| s_id | Total |
+------+-------+
|  101 |     3 |
|  102 |     3 |
|  103 |     2 |
|  104 |     2 |
|  105 |     3 |
|  106 |     1 |
|  107 |     2 |
| NULL |    16 |
+------+-------+
8 rows in set (0.00 sec)

mysql>


    多字段分组
mysql>  SELECT * FROM fruits group by s_id,f_name;
+------+------+------------+---------+
| f_id | s_id | f_name     | f_price |
+------+------+------------+---------+
| a1   |  101 | apple      |    5.20 |
| b1   |  101 | blackberry |   10.20 |
| c0   |  101 | cherry     |    3.20 |
| t1   |  102 | banana     |   10.30 |
| t2   |  102 | grape      |    5.30 |
| bs1  |  102 | orange     |   11.20 |
| a2   |  103 | apricot    |    2.20 |
| o2   |  103 | coconut    |    9.20 |
| b2   |  104 | berry      |    7.60 |
| l2   |  104 | lemon      |    6.40 |
| bs2  |  105 | melon      |    8.20 |
| m2   |  105 | xbabay     |    2.60 |
| m3   |  105 | xxtt       |   11.60 |
| m1   |  106 | mango      |   15.60 |
| t4   |  107 | xbababa    |    3.60 |
| b5   |  107 | xxxx       |    3.60 |
+------+------+------------+---------+
16 rows in set (0.00 sec)

mysql>

    GROUP BY和ORDER BY 一起使用完成对分组的排序
mysql> CREATE TABLE orderitems
    -> (
    ->   o_num      int          NOT NULL,
    ->   o_item     int          NOT NULL,
    ->   f_id       char(10)     NOT NULL,
    ->   quantity   int          NOT NULL,
    ->   item_price decimal(8,2) NOT NULL,
    ->   PRIMARY KEY (o_num,o_item)
    -> ) ;
Query OK, 0 rows affected (0.20 sec)

mysql> INSERT INTO orderitems(o_num, o_item, f_id, quantity, item_price)
    -> VALUES(30001, 1, 'a1', 10, 5.2),
    -> (30001, 2, 'b2', 3, 7.6),
    -> (30001, 3, 'bs1', 5, 11.2),
    -> (30001, 4, 'bs2', 15, 9.2),
    -> (30002, 1, 'b3', 2, 20.0),
    -> (30003, 1, 'c0', 100, 10),
    -> (30004, 1, 'o2', 50, 2.50),
    -> (30005, 1, 'c0', 5, 10),
    -> (30005, 2, 'b1', 10, 8.99),
    -> (30005, 3, 'a2', 10, 2.2),
    -> (30005, 4, 'm1', 5, 14.99);
Query OK, 11 rows affected (0.08 sec)
Records: 11  Duplicates: 0  Warnings: 0

mysql>
mysql> SELECT o_num,  SUM(quantity * item_price) AS orderTotal
    -> FROM orderitems
    -> GROUP BY o_num
    -> HAVING SUM(quantity*item_price) >= 100;
+-------+------------+
| o_num | orderTotal |
+-------+------------+
| 30001 |     268.80 |
| 30003 |    1000.00 |
| 30004 |     125.00 |
| 30005 |     236.85 |
+-------+------------+
4 rows in set (0.01 sec)

mysql> SELECT o_num,  SUM(quantity * item_price) AS orderTotal
    -> FROM orderitems
    -> GROUP BY o_num
    -> HAVING SUM(quantity*item_price) >= 100
    -> ORDER BY orderTotal;
+-------+------------+
| o_num | orderTotal |
+-------+------------+
| 30004 |     125.00 |
| 30005 |     236.85 |
| 30001 |     268.80 |
| 30003 |    1000.00 |
+-------+------------+
4 rows in set (0.00 sec)

mysql>

    12. 使用LIMIT限制查询结果数量

    mysql> SELECT * From fruits LIMIT 4;
+------+------+------------+---------+
| f_id | s_id | f_name     | f_price |
+------+------+------------+---------+
| a1   |  101 | apple      |    5.20 |
| a2   |  103 | apricot    |    2.20 |
| b1   |  101 | blackberry |   10.20 |
| b2   |  104 | berry      |    7.60 |
+------+------+------------+---------+
4 rows in set (0.00 sec)

mysql> SELECT * From fruits LIMIT 4, 3;
+------+------+--------+---------+
| f_id | s_id | f_name | f_price |
+------+------+--------+---------+
| b5   |  107 | xxxx   |    3.60 |
| bs1  |  102 | orange |   11.20 |
| bs2  |  105 | melon  |    8.20 |
+------+------+--------+---------+
3 rows in set (0.00 sec)

mysql>

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