How can I add a character into a specified position into string in SQL SERVER?

Question

I have a varchar field like:

195500
122222200

I need to change these values to:

1955.00
1222222.00

Answer 1

Ran into something similar and came up with this, could probably change this to a function/SP to make it reusable. Scenario faced was inserting a specified character at different positions within the string, for a certain number of times.

/*
 --- passed in string or column,  N'C4CB6B22250B'
 --- desired output, C4:CB:6B:22:25:0D
 --- Test values 
 --- declare @strToChange varchar(50) = N'C4:CB:6B:22:25:0B'
 --- declare @strToChange varchar(50) = N'C4CB6B22250B'
*/


declare @strToChange varchar(50) = N'C4CB6B22250B'
IF(SELECT LEN(@strToChange) - LEN(REPLACE(@strToChange, ':', ''))) > 0
    BEGIN
        ---returns count of specified char
        SELECT LEN(@strToChange) - LEN(REPLACE(@strToChange, ':', ''))
    END
        ELSE
    BEGIN
        declare @charCount int = 5; --# of times to insert the char
        declare @shiftPosition int = 2; -- inital insertion shift
        While(@charCount > 0)
            begin
            SET @strToChange = LEFT(@strToChange,len(@strToChange)- @shiftPosition) + ':' + RIGHT(@strToChange,@shiftPosition)
            SET @charCount = @charCount - 1 --decrement charCount for each added char
            SET @shiftPosition = @shiftPosition + 3 ---increment shift position by 3 for the new char and the chars that were already there
        end
    SELECT @strToChange
END