MySQL - 仅从varchar列中选择数值

Question

考虑下表：

create table mixedvalues (value varchar(50));

insert into mixedvalues values ('100');
insert into mixedvalues values ('ABC100');
insert into mixedvalues values ('200');
insert into mixedvalues values ('ABC200');
insert into mixedvalues values ('300');
insert into mixedvalues values ('ABC300');
insert into mixedvalues values ('400');
insert into mixedvalues values ('ABC400');
insert into mixedvalues values ('500');
insert into mixedvalues values ('ABC500');

如何编写一个只返回数字值的select语句，如

100
200
300
400
500

SQLFiddle

Answer 1

SELECT * 
FROM mixedvalues 
WHERE value REGEXP '^[0-9]+$';

Answer 2

你很亲密：

SELECT * 
FROM mixedvalues 
WHERE value > 0;

SQLFiddle

Answer 3

SELECT * 
FROM mixedvalues 
WHERE concat('',value * 1) = value;

参考：Detect if value is number in MySQL

Answer 4

列表项的字符串以数字开头

$string = "Test";

select * from table where columnname REGEXP "$string-*[0-9]+"; 

Answer 5

SELECT * FROM mixedvalues 
WHERE value > 0 
ORDER BY CAST(value as SIGNED INTEGER) ASC

Answer 6

您可以使用ISNUMERIC功能过滤结果集：

SELECT value
FROM #mixedvalues 
where ISNUMERIC(value)=1