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Editorial Team
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Asked: 2026-05-15T21:26:57+00:00

For example, if all entries in a particular column have the form [a-z]+[0-9]+, how

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For example, if all entries in a particular column have the form [a-z]+[0-9]+, how can one extract just the leading letters, so that asdf123 and as3456 return ‘asdf’ and ‘as’, respectively?

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1 Answer

  1. Editorial Team

    This is not posible with mysql regex capablities (unless installing some udf’s which appear to be designed for that). Technically, as [0-9] is a limited set you could throw 10 LOCATE‘s in LEAST (watch out for & invalitdate 0), and use SUBSTRING. Not a pretty picture:

    SET @var ='asjdasd35433';
SELECT SUBSTRING(@var,1,
  LEAST(
    IF(LOCATE(0,@var)=0,LENGTH(@var),LOCATE(0,@var)),
    IF(LOCATE(1,@var)=0,LENGTH(@var),LOCATE(1,@var)),
    IF(LOCATE(2,@var)=0,LENGTH(@var),LOCATE(2,@var)),
    IF(LOCATE(3,@var)=0,LENGTH(@var),LOCATE(3,@var)),
    IF(LOCATE(4,@var)=0,LENGTH(@var),LOCATE(4,@var)),
    IF(LOCATE(5,@var)=0,LENGTH(@var),LOCATE(5,@var)),
    IF(LOCATE(6,@var)=0,LENGTH(@var),LOCATE(6,@var)),
    IF(LOCATE(7,@var)=0,LENGTH(@var),LOCATE(7,@var)),
    IF(LOCATE(8,@var)=0,LENGTH(@var),LOCATE(8,@var)),
    IF(LOCATE(9,@var)=0,LENGTH(@var),LOCATE(9,@var))
   ) -1 ) as 'result';
+---------+
| result  |
+---------+
| asjdasd | 
+---------+

    If you need it look at udf’s. Otherwise you’re just better of fetching the field and manipulate it outside MySQL.

    Edit: if the number fits in an integer, dirty hackery could result in :

    SET @var ='asjdasd35433';
SELECT SUBSTRING(@var,1,LENGTH(@var)-LENGTH(CAST(REVERSE(@var) as UNSIGNED)));
+---------+
| result  |
+---------+
| asjdasd |
+---------+
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