问题描述

我有一些包含字母数字值的字符串输出.我只想从该字符串中获取数字.我怎样才能通过查询获取这个?我可以使用哪个 MySql 函数?

I have some string output which contain alphanumeric value. I want to get only Digits from that string. how can I fetch this by query? which MySql function can I Use?

我的查询就像:

select DISTINCT SUBSTRING(referrerURL,71,6)   
from   hotshotsdblog1.annonymoustracking   
where  advertiserid = 10 
limit  10;

输出:

100683
101313
19924&
9072&h
12368&
5888&h
10308&
100664
1&hash
101104

我想要输出如下:

100683
101313
19924
9072
12368
5888 
10308
100664
1
101104

推荐答案

如果字符串以数字开头，则包含非数字字符，可以使用CAST() 函数或通过添加 0:

If the string starts with a number, then contains non-numeric characters, you can use the CAST() function or convert it to a numeric implicitly by adding a 0:

SELECT CAST('1234abc' AS UNSIGNED); -- 1234
SELECT '1234abc'+0; -- 1234

要从任意字符串中提取数字，您可以添加自定义函数 像 这个:

To extract numbers out of an arbitrary string you could add a custom function like this:

DELIMITER $$

CREATE FUNCTION `ExtractNumber`(in_string VARCHAR(50)) 
RETURNS INT
NO SQL
BEGIN
    DECLARE ctrNumber VARCHAR(50);
    DECLARE finNumber VARCHAR(50) DEFAULT '';
    DECLARE sChar VARCHAR(1);
    DECLARE inti INTEGER DEFAULT 1;

    IF LENGTH(in_string) > 0 THEN
        WHILE(inti <= LENGTH(in_string)) DO
            SET sChar = SUBSTRING(in_string, inti, 1);
            SET ctrNumber = FIND_IN_SET(sChar, '0,1,2,3,4,5,6,7,8,9'); 
            IF ctrNumber > 0 THEN
                SET finNumber = CONCAT(finNumber, sChar);
            END IF;
            SET inti = inti + 1;
        END WHILE;
        RETURN CAST(finNumber AS UNSIGNED);
    ELSE
        RETURN 0;
    END IF;    
END$$

DELIMITER ;

一旦定义了函数，就可以在查询中使用它:

Once the function is defined, you can use it in your query:

SELECT ExtractNumber("abc1234def") AS number; -- 1234

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