mysqlregexregex-replace

mySQL regex_replace remove all beginning numbers from mixed input

I need a regex pattern to remove all numeric input from the beginning of a field that stops at the first alphabetic character and leaves any remaining numbers that follow alphabetic characters.

Here is the simplest test case.

CREATE TABLE tempdemo (tdfields varchar(10));
INSERT INTO tempdemo (tdfields) VALUES ('1'), ('11'), ('111'), ('a'), ('ab'), ('abc'), ('1a'), ('a1');

SELECT REGEXP_REPLACE(tdfields, '^[0-9]*$', '') FROM tempdemo;

From the code, I would like the following output: :blank:, :blank:, :blank:, a, ab, abc, a, a1

Right now, the regex pattern leaves '1a' instead of 'a' which is undesireable.

Any help would be greatly appreciated. Thanks.

Solution

  • You can use

    CREATE TABLE tempdemo (tdfields varchar(10));
INSERT INTO tempdemo (tdfields) VALUES ('1'), ('11'), ('111'), ('a'), ('ab'), ('abc'), ('1a'), ('a1');

SELECT REGEXP_REPLACE(tdfields, '^[0-9]+', '') FROM tempdemo;

    It will remove one or more digits from the start of the string.

    More details:

    $ matches the start of string position.

    Note that ^[0-9]* is not a good pattern here since it matches any string, and + variation will only match when necessary, when there are digits at the start of the string.