Question

I have a string like prop234 the alphabet part has fixed length but the numeric part may be of any length

I have to get the numeric part from the string in T-SQL (on SQL Server 2008)

I tried with SUBSTRING function but I don’t know the length of the numeric part so can’t provide third parameter i.e. length

SUBSTRING ( expression ,start , length )

I know the start index but length can be anything

One solution is

SELECT substring([ColumnName], 5, LEN(ColumnName) - 4)

as start index is fixed i.e. length of alphabet part is 4 (fixed)

Is there any better solution for this and what if the length of alphabetic part is not constant?

Answer 1

select stuff('prop234', 1,4,'')

and if the length is not a constant:

declare @t table(expression varchar(100))
insert @t values('propprop234')

select stuff(expression, 1, patindex('%_[0-9]%', expression), '') from @t

EDIT: To make sure bad data is handled, such as no text first or no number last, here is a slightly different approach:

select stuff(expression, 1,patindex('%[^0-9][0-9]%', expression + '0'), '') 
from @t