选择以数字开头的值

Question

在MySQL上,我有一个表,其中包含以数字开头的数据

如何选择仅以数字开头的行？

Answer 1

SELECT * FROM YourTable WHERE YourColumn regexp '^[0-9]+'

Answer 2

你可以做:

SELECT *
FROM MyTable
WHERE MyColumn REGEXP '^[0-9]';

使用的正则表达式是^[0-9].

^    - Start anchor, used to ensure the pattern matches start of the string.
[    - Start of character class.
0-9  - Any digit
]    - End of character class

实际上,我们正在尝试在以数字开头的列中选择那些值.

演示:

mysql> select * from tab;
+-------+
| col   |
+-------+
| 1foo  |
| foo   |
| 10foo |
| foo10 |
+-------+
4 rows in set (0.00 sec)

mysql> select * from tab where col regexp '^[0-9]';
+-------+
| col   |
+-------+
| 1foo  |
| 10foo |
+-------+
2 rows in set (0.00 sec)

Answer 3

另一种方式:

WHERE LEFT(columnName,1) IN ('0','1','2','3','4','5','6','7','8','9')

使用常见的字符集和排序规则,这将工作并使用列上的索引:

WHERE columnName >= '0' AND columnName < ':'

Answer 4

也

SELECT * FROM YourTable
WHERE YourColumn LIKE '[0-9]%';