Comments on: SQL SERVER – Check If String is a Palindrome in Using T-SQL Script – Reverse Function

By: harsh

harsh — Fri, 08 Mar 2013 12:43:26 +0000

My earlier solution was not properly posted due to greater than sign.

DECLARE @PalinString VARCHAR(256)
SET @PalinString= ‘A man, a plan, a canal – Panama!’
DECLARE @I INT
DECLARE @J INT
SET @I=1
SET @J= LEN(@PalinString)
DECLARE @RESULT AS VARCHAR(20)
SET @RESULT=’Palindrome’
DECLARE @A INT
DECLARE @B INT
WHILE (@J>@I)
BEGIN
SET @A=ASCII(UPPER(SUBSTRING(@PalinString,@I,1)))
SET @B=ASCII(UPPER(SUBSTRING(@PalinString,@J,1)))
IF NOT((@A>=48 AND 57>=@A) OR (@A>=65 AND 90>=@A))
BEGIN
SET @I=@I+1
CONTINUE
END
IF NOT((@B>=48 AND 57>=@B) OR (@B>=65 AND 90>=@B))
BEGIN
SET @J=@J-1
CONTINUE
END
IF @A!=@B
BEGIN
SET @RESULT= ‘Not Palindrome’
BREAK
END
SET @I=@I+1
SET @J=@J-1
END
PRINT @RESULT

By: CHANDU

CHANDU — Fri, 08 Mar 2013 10:34:32 +0000

Hi Sanjay,

For that you have to use NVARCHAR…
See this
select REPLACE(N’ટેબલ’, ‘ ‘, ”) , REVERSE(REPLACE(N’ટેબલ’, ‘ ‘, ”))

By: harsh

harsh — Fri, 08 Mar 2013 04:26:12 +0000

REVERSE & Removing spaces is a better option. I have written one solution, which will consider only alphabets & digits . So, it will ignore space,exclamation mark ,comma etc.

DECLARE @PalinString VARCHAR(256)
SET @PalinString= ‘A man, a plan, a canal – Panama!’
DECLARE @I INT
DECLARE @J INT
SET @I=1
SET @J= LEN(@PalinString)
DECLARE @RESULT AS VARCHAR(20)
SET @RESULT=’Palindrome’
DECLARE @A INT
DECLARE @B INT
WHILE (@I=48 AND @A=65 AND @A=48 AND @B=65 AND @B<= 90))
BEGIN
SET @J=@J-1
CONTINUE
END
IF @A!=@B
BEGIN
SET @RESULT= 'Not Palindrome'
BREAK
END
SET @I=@I+1
SET @J=@J-1
END
PRINT @RESULT

–Result is Palindrome

By: Sanjay Monpara

Sanjay Monpara — Thu, 07 Mar 2013 14:49:37 +0000

DECLARE @PalinString VARCHAR(256)
SET @PalinString = ‘ટેબલ’

SELECT CASE WHEN REPLACE(@PalinString, ‘ ‘, ”) = REVERSE(REPLACE(@PalinString, ‘ ‘, ”))
THEN ‘Palindrome’
ELSE ‘Not Palindrome’ END AS [Answer]
GO

This is showing ‘ટેબલ’ is Palindrome
because output of query,
select REPLACE(‘ટેબલ’, ‘ ‘, ”) , REVERSE(REPLACE(‘ટેબલ’, ‘ ‘, ”))
is
???? ????

By: Fabrizio Faleni

Fabrizio Faleni — Thu, 07 Mar 2013 13:31:47 +0000

Thanks Pinal!
Not only you’ll have to remove punctuation marks but also remove accents in all the languages that use them (which are a lot!). For example in this French palindrome “Ainsi Anaïs nia” the umlaut should be removed, such as in the Italian Palindrome “A Natale è la tana” should the grave accent. Do you have a smart solution for this too?
Kind regards!

By: Eduard Uta

Eduard Uta — Thu, 07 Mar 2013 13:01:40 +0000

Hi,

Definitely the REVERSE function does the job much easier but just for fun
here is an alternative for this “challenge”:

declare @PalinString VARCHAR(256) = ‘Was it a car or a cat I saw’
declare @wlen int
declare @answer varchar(100)

set @PalinString = REPLACE(@PalinString, ‘ ‘, ”)
set @wlen = LEN(@PalinString)

if @wlen = 0
begin
set @answer = ‘Empty. Please add a string’
end
else if @wlen = 1
begin
set @answer = ‘One character => Palindrome’
end
else
begin
while (@wlen > 1)
begin
if LEFT(@PalinString, 1) = RIGHT(@PalinString, 1)
begin
set @PalinString = LEFT(@PalinString, LEN(@PalinString)-1)
set @PalinString = RIGHT(@PalinString, LEN(@PalinString)-1)
set @wlen = LEN(@PalinString)
set @answer = ‘Palindrome’
end
else
begin
set @answer = ‘Not Palindrome’
set @wlen = 0
end
end
end

print ‘The String is ‘ + @answer
select Answer = @answer
go

By: Eduard Uta

Eduard Uta — Thu, 07 Mar 2013 12:58:58 +0000

Hi,

Definitely the REVERSE function does the job much easier and faster but just for fun I give you an alternative :D

declare @PalinString VARCHAR(256) = ‘Was it a car or a cat I saw’
declare @wlen int
declare @answer varchar(100)

set @PalinString = REPLACE(@PalinString, ‘ ‘, ”)
set @wlen = LEN(@PalinString)

print ‘The String is ‘ + @answer
select Answer = @answer
go

By: Agustin

Agustin — Thu, 07 Mar 2013 12:40:11 +0000

Nice

By: Vishal

Vishal — Thu, 07 Mar 2013 11:34:50 +0000

જા રે બાવા બારેજા ……..

By: Shorty

Shorty — Thu, 07 Mar 2013 10:54:42 +0000

Seems valid. Never had this requirement myself, but now that I think about it your function is a good way to do it. Well done,sir! :)