Replacing column from query via patterns

Question

How to replace all column in the string

DECLARE @invalidColumns varchar(200) = 'abc, xyz'

DECLARE @sqltext varchar(max) = '((abc = ''sometext'') OR (xyz    = '' some more text'')) OR
                                 (pqr = ''vb'') AND ( abc != ''  text '')
                                 OR ((hht = ''asd asd'') AND ( xyz =   ''  More text  '' ))
'

in above example I have to search for column abc and xyz in @sqlText and replace them all with 1=1

so the final output should look like

((1 = 1) OR (1    = 1)) OR
                             (pqr = ''vb'') AND ( 1 != 1)
                             OR ((hht = ''asd asd'') AND ( 1 =  1 ))

I tried to do in this way but it seems like replace function is not working with patterns, also it will do for only first finding. There may be possibility that column abc and xyz may appear multiple times in a statement.

SELECT CASE WHEN PATINDEX('%abc% ''%',@sqltext) > 0
            THEN REPLACE (@sqlText,'%abc% ''%', '1=1')
            END

Any help

Edit

I tried this, but it is not giving me proper result

DECLARE @len INT
DECLARE @initializor INT = 1
DECLARE @First INT
DECLARE @Result VARCHAR(max) SET @Result = ''
DECLARE @EndPattern INT
SET @len = LEN(@sqltext)


WHILE( @initializor <= @len)
BEGIN
        SET @First = PATINDEX('%abc% ''%', SUBSTRING(@sqltext, @initializor, @Len))
         SET @EndPattern = 1
              WHILE PATINDEX('%abc% ''%', SUBSTRING(@sqltext, @initializor, @EndPattern)) = 0
            SET @EndPattern = @EndPattern + 1

        IF COALESCE(@First, 0) <> 0
        BEGIN
             SET @Result = @Result + SUBSTRING(@sqltext, @initializor, @First - 1)
             SET @initializor = @initializor + @First - 1

             SET @EndPattern = 1
              WHILE PATINDEX('%abc% ''%', SUBSTRING(@sqltext, @initializor, @EndPattern)) = 0
            SET @EndPattern = @EndPattern + 1
         -- Find end of pattern range
         WHILE PATINDEX('%abc% ''%', SUBSTRING(@sqltext, @initializor, @EndPattern)) > 0
               AND @Len >= (@initializor + @EndPattern - 1)
                    SET @EndPattern = @EndPattern + 1

         --Either at the end of the pattern or @Next + @EndPattern = @Len
         SET @Result = @Result + '''1=1'''
         SET @initializor = @initializor + @EndPattern - 1


        END


        SET @initializor = @initializor + 1;
END


SELECT @Result

Answer 1

Introduce some more information about the replace text. Here is a great example:

DECLARE @invalidColumns varchar(max) = replace('abc, xyz', ' ', '')

DECLARE @sqltext varchar(max) = ''

;WITH t1 as
(
SELECT '(*'    pat, '(abc = ''sometext'')' txt, 'abc' col
UNION ALL SELECT 'OR *)' pat, 'OR (xyz = '' some more text'')' txt, 'xyz' col
UNION ALL SELECT 'OR *'  pat, '(pqr = ''vb'')' txt, 'pqr' col
UNION ALL SELECT 'AND *' pat, 'abc != ''  text ''' txt, 'abc' col
UNION ALL SELECT 'OR (*' pat, '(hht = ''asd asd'')' txt, 'hht' col
UNION ALL SELECT 'AND(*)' pat, 'xyz =   ''''''' txt, 'xyz' col
), t2 as
(
SELECT t.c.value('.', 'VARCHAR(20)') col
FROM (
SELECT x = CAST('<t>' + 
    REPLACE(@invalidColumns, ',', '</t><t>') + '</t>' AS XML)
) a
CROSS APPLY x.nodes('/t') t(c)
) 
SELECT @sqltext = @sqltext 
+ replace(t1.pat, '*', case when t2.col is null then t1.txt else ' 1 = 1 ' end)
FROM t1
LEFT JOIN t2 on t1.col = t2.col

SELECT @sqltext