📜  SQL-LIKE子句

📅  最后修改于: 2020-12-29 04:34:59             🧑  作者: Mango


SQL LIKE子句用于使用通配符运算符将值与相似值进行比较。与LIKE运算符一起使用两个通配符。

  • 百分号(%)
  • 下划线(_)

百分号代表零个,一个或多个字符。下划线表示单个数字或字符。这些符号可以组合使用。

句法

%和_的基本语法如下-

SELECT FROM table_name
WHERE column LIKE 'XXXX%'

or 

SELECT FROM table_name
WHERE column LIKE '%XXXX%'

or

SELECT FROM table_name
WHERE column LIKE 'XXXX_'

or

SELECT FROM table_name
WHERE column LIKE '_XXXX'

or

SELECT FROM table_name
WHERE column LIKE '_XXXX_'

您可以使用AND或OR运算符组合N个条件。在此,XXXX可以是任何数字或字符串值。

下表列出了一些示例,这些示例显示WHERE部分具有不同的LIKE子句,其中包含’%’和’_’运算符-

Sr.No. Statement & Description
1

WHERE SALARY LIKE ‘200%’

Finds any values that start with 200.

2

WHERE SALARY LIKE ‘%200%’

Finds any values that have 200 in any position.

3

WHERE SALARY LIKE ‘_00%’

Finds any values that have 00 in the second and third positions.

4

WHERE SALARY LIKE ‘2_%_%’

Finds any values that start with 2 and are at least 3 characters in length.

5

WHERE SALARY LIKE ‘%2’

Finds any values that end with 2.

6

WHERE SALARY LIKE ‘_2%3’

Finds any values that have a 2 in the second position and end with a 3.

7

WHERE SALARY LIKE ‘2___3’

Finds any values in a five-digit number that start with 2 and end with 3.

让我们以一个真实的示例为例,考虑具有如下所示记录的CUSTOMERS表。

+----+----------+-----+-----------+----------+
| ID | NAME     | AGE | ADDRESS   | SALARY   |
+----+----------+-----+-----------+----------+
|  1 | Ramesh   |  32 | Ahmedabad |  2000.00 |
|  2 | Khilan   |  25 | Delhi     |  1500.00 |
|  3 | kaushik  |  23 | Kota      |  2000.00 |
|  4 | Chaitali |  25 | Mumbai    |  6500.00 |
|  5 | Hardik   |  27 | Bhopal    |  8500.00 |
|  6 | Komal    |  22 | MP        |  4500.00 |
|  7 | Muffy    |  24 | Indore    | 10000.00 |
+----+----------+-----+-----------+----------+

下面是一个示例,它将显示CUSTOMERS表中的所有记录,其中SALARY以200开头。

SQL> SELECT * FROM CUSTOMERS
WHERE SALARY LIKE '200%';

这将产生以下结果-

+----+----------+-----+-----------+----------+
| ID | NAME     | AGE | ADDRESS   | SALARY   |
+----+----------+-----+-----------+----------+
|  1 | Ramesh   |  32 | Ahmedabad |  2000.00 |
|  3 | kaushik  |  23 | Kota      |  2000.00 |
+----+----------+-----+-----------+----------+