Reverse integer without using REVERSE() from the table using SQL Serve

Saroj Bhandari

5y947

How to Reverse integer without using REVERSE() from the table

Suppose, i have table name Numbers and column name num which has a value of 123

how do i reverse it to 321 ?

Thank YOu

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Satya Karki5y ago
Hi,

Check this blog

https://sqlwithmanoj.com/2011/08/18/reverse-a-string-without-using-tsqls-reverse-function/
Rijwan Ansari5y ago
Hi,
You can do in this way
DECLARE @StringToReverse VARCHAR(55)
Select @StringToReverse = ColumnNameToReverse from the TableName

;WITH cte AS (
      SELECT @StringToReverse AS string, CAST('' AS VARCHAR(55)) AS revStr, LEN(@StringToReverse) AS ln
      UNION ALL
      SELECT SUBSTRING(string,0,ln) AS string, CAST(revStr + SUBSTRING(string,ln,1) AS VARCHAR(55)) AS revStr, ln-1 AS ln
      FROM cte
      WHERE ln >= 1)
SELECT @StringToReverse AS String, revStr
FROM cte
WHERE ln = 0
Regards
Rijwan
Siddharth Gajbhiye5y ago
Hello Saroj

You must create a function
CREATE function StringReverse(@inputstring varchar(max))

returns varchar(max)

AS

BEGIN

  DECLARE @i int,

          @Result varchar(max)

  SET @Result=''

  SET @i = 1

  WHILE @i <= LEN(@inputstring)

  BEGIN

    SET @Result = SUBSTRING(@inputstring,@i,1) + @Result

    SET @i=@i + 1

  END

  RETURN @Result

END

Execution of function -
select dbo.StringReverse('xyz123abc')

Reference : https://stackoverflow.com/questions/57972660/how-do-i-reverse-a-string-in-sql-server-without-using-reverse-function
Jignesh Kumar5y ago
Hi Saroj,

You can create function and use that function in select statement,
CREATE function IntegerReverse(@number int)
returns int
AS
BEGIN
  DECLARE @i int,
          @Result int
  SET @Result=(
SELECT (SELECT N

        FROM (SELECT TOP (LEN(@number))

              SUBSTRING(CAST(@number AS VARCHAR(19)),N,1)

              FROM (VALUES(1),(2),(3),(4),(5),(6),(7),(8),(9),

                          (10),(11),(12),(13),(14),(15),(16),(17),

                          (18),(19))a(N)

              WHERE N <= (LEN(@number))

              ORDER BY N DESC) b(N)
        FOR XML PATH(''), TYPE).value('.', 'VARCHAR(19)'))
  RETURN @Result
END
You can call this function as below.
select dbo.IntegerReverse(num) from Numbers