I'm using SQL Server and I want to check whether the given string is a palindrome or not - but without using the reverse function.
There are multiple ways to achieve this. One of them is to check first and last character, slicing them if they're equal and continuing the process in a loop.
DECLARE #string NVARCHAR(100)
DECLARE #counter INT
SET #string = 'Your string'
SET #counter = LEN(#string)/2
WHILE (#counter > 0)
BEGIN
IF LEFT(#string,1) = RIGHT(#string,1)
BEGIN
SET #string = SUBSTRING(#string,2,len(#string)-2)
SET #counter = #counter - 1
END
ELSE
BEGIN
PRINT ('Given string is not a Palindrome')
BREAK
END
END
IF(#counter = 0)
PRINT ('Given string is a Palindrome')
A select without loops
DECLARE #Test VARCHAR(100)
SELECT #Test = 'qwerewq'
SELECT CASE WHEN LEFT(#Test, LEN(#Test)/2) =
(
SELECT '' + SUBSTRING(RIGHT(#Test, LEN(#Test)/2), number, 1)
FROM master.dbo.spt_values
WHERE type='P' AND number BETWEEN 1 AND LEN(#Test)/2
ORDER BY number DESC
FOR XML PATH('')
)
THEN 1
ELSE 0
END
Here's an example using LEFT and RIGHT. I use the #count variable to change position, then grab the left-most and right-most char:
DECLARE #mystring varchar(100) = 'redivider'
DECLARE #count int = 1
WHILE (#count < LEN(#mystring) / 2) AND #count <> 0
BEGIN
IF (RIGHT(LEFT(#mystring, #count), 1) <> LEFT(RIGHT(#mystring, #count), 1))
SET #count = 0
ELSE SET #count += 1
END
SELECT CASE WHEN #count = 0
THEN 'Not a Palindrome'
ELSE 'Palindrome'
END [Result]
Related
I want o/p of select statement so that it will show alternate letters of given uppercase string in lowercase.
For example if input string is:
ABCDEFG
then output should be:
AbCdEfG
You can create a function containing a simple loop that performs upper/lower casing on your string.
For example in SQL Server:
CREATE FUNCTION [dbo].[AlternateCase]
(
#input_string nvarchar(max)
)
returns nvarchar(max)
as
begin
declare #counter int
declare #result nvarchar (max)
set #counter = 0
set #result = ''
while #counter <= LEN(#input_string)
begin
if #counter % 2 = 0
set #result = #result + lower(substring(#input_string, #counter, 1))
else
set #result = #result + upper(substring(#input_string, #counter, 1))
set #counter = #counter + 1
end
return #result
end
Now you can use the new function in your select statements:
select [dbo].[AlternateCase]('ABCDEFG')
and this select will return:
AbCdEfG
I am importing working with data imported from excel files. There is a column with a string that can contain multiple numbers. I am trying to extract the largest number in the string or a 0 if there is no string.
The strings are in formats similar to:
"100% post-consumer recycled paper, 50% post-consumer recycled cover, 90% post-consumer recycled wire."
"Paper contains 30% post-consumer content."
or sometimes a empty string or null.
Given the irregular formatting of the string I am having trouble and any help would be appreciated.
Here's a scalar function that will take a string as an input and return the largest whole number it finds (up to a maximum of 3 digits, but from your question I've assumed you're dealing with percentages. If you need more digits, repeat the IF statements ad infinitum).
Paste this into SSMS and run it to create the function. To call it, do something like:
SELECT dbo.GetLargestNumberFromString(MyStringField) as [Largest Number in String]
FROM MyMessedUpData
Function:
CREATE FUNCTION GetLargestNumberFromString
(
#s varchar(max)
)
RETURNS int
AS
BEGIN
DECLARE #LargestNumber int, #i int
SET #i = 1
SET #LargestNumber = 0
WHILE #i <= LEN(#s)
BEGIN
IF SUBSTRING(#s, #i, 3) like '[0-9][0-9][0-9]'
BEGIN
IF CAST(SUBSTRING(#s, #i,3) as int) > #LargestNumber OR #LargestNumber IS NULL
SET #LargestNumber = CAST(SUBSTRING(#s, #i,3) as int);
END
IF SUBSTRING(#s, #i, 2) like '[0-9][0-9]'
BEGIN
IF CAST(SUBSTRING(#s, #i,2) as int) > #LargestNumber OR #LargestNumber IS NULL
SET #LargestNumber = CAST(SUBSTRING(#s, #i,2) as int);
END
IF SUBSTRING(#s, #i, 1) like '[0-9]' OR #LargestNumber IS NULL
BEGIN
IF CAST(SUBSTRING(#s, #i,1) as int) > #LargestNumber
SET #LargestNumber = CAST(SUBSTRING(#s, #i,1) as int);
END
SET #i = #i + 1
CONTINUE
END
RETURN #LargestNumber
END
Pull the data into SQL as-is
Write a query to get a distinct list of options in that column
Add a new column to store the desired value
Write an update statement to populate the new column
As far as determining the largest size, I think you need to look at your data set first, but the update could be as simple as:
DECLARE #COUNTER INT=1000
While EXISTS (SELECT * FROM <Table> WHERE NewColumn is NULL) AND #COUNTER>=0
BEGIN
UPDATE <Table> SET NewColumn=#COUNTER WHERE <SearchColumn> LIKE '%' + CONVERT(VARCHAR,#COUNTER) + '%' AND NewColumn is NULL
SET #COUNTER=#COUNTER-1
END
SQL Fiddle Demo
Generate the LEN(txt) possible RIGHT() fragments of txt. Trim each fragment at the first non-digit character. Test if the remainder is an int. Return the MAX().
SELECT
txt
,MAX(TRY_CONVERT(int,LEFT(RIGHT(txt,i),PATINDEX('%[^0-9]%',RIGHT(txt,i)+' ')-1)))
FROM MyTable
CROSS APPLY (
SELECT TOP(LEN(txt)) ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) i FROM master.dbo.spt_values a, master.dbo.spt_values b
) x
GROUP BY txt
I ended up creating a function that handled it. Here is the code:
CREATE FUNCTION [dbo].[cal_GetMaxPercentFromString]
RETURNS float
AS
BEGIN
declare #Numbers Table(number float)
insert into #Numbers
Select 0
declare #temp as varchar(2000) = #string
declare #position int, #length int, #offset int
WHILE CHARINDEX('%', #temp) > 0
BEGIN
set #position = CHARINDEX('%', #temp)
set #offset = 1
set #length = -1
WHILE #position - #offset > 0 and #length < 0
BEGIN
if SUBSTRING(#temp, #position - #offset, 1) not LIKE '[0-9]'
set #length = #offset - 1
set #offset = #offset + 1
END
if #length > 0
BEGIN
insert into #Numbers
select CAST(SUBSTRING(#temp, #position - #length, #length) as float)
END
set #temp = SUBSTRING(#temp, 1, #position - 1) + SUBSTRING(#temp, #position + 1, LEN(#temp) - #position)
END
declare #return as float
select #return = MAX(number) from #Numbers
return #return
END
I need to compare two strings character by character using T-SQL. Let's assume i have twor strings like these:
123456789
212456789
Every time the character DO NOT match, I would like to increase the variable #Diff +=1. In this case the first three characters differ. So the #Diff = 3 (0 would be default value).
Thank you for all suggestions.
for columns in table you don't want to use row by row approach, try this one:
with cte(n) as (
select 1
union all
select n + 1 from cte where n < 9
)
select
t.s1, t.s2,
sum(
case
when substring(t.s1, c.n, 1) <> substring(t.s2, c.n, 1) then 1
else 0
end
) as diff
from test as t
cross join cte as c
group by t.s1, t.s2
=>sql fiddle demo
This code should count the differences in input strings and save this number to counter variable and display the result:
declare #var1 nvarchar(MAX)
declare #var2 nvarchar(MAX)
declare #i int
declare #counter int
set #var1 = '123456789'
set #var2 = '212456789'
set #i = LEN(#var1)
set #counter = 0
while #i > 0
begin
if SUBSTRING(#var1, #i, 1) <> SUBSTRING(#var2, #i, 1)
begin
set #counter = #counter + 1
end
set #i = #i - 1
end
select #counter as Value
The below query compares, shows the different characters and bring you the count of differences
Declare #char1 nvarchar(1), #char2 nvarchar(1), #i int = 1, #max int
Declare #string1 nvarchar(max) = '123456789'
, #string2 nvarchar(max) = '212456789'
Declare #diff_table table (pos int , string1 nvarchar(50) , string2 nvarchar(50), Status nvarchar(50))
Set #max = (select case when len(#String1+'x')-1 > len(#string2+'x')-1 then len(#String1+'x')-1 else len(#string2+'x')-1 end)
while #i < #max +1
BEGIN
Select #char1 = SUBSTRING(#string1,#i,1), #char2 = SUBSTRING(#string2,#i,1)
INSERT INTO #diff_table values
(
#i,
case when UNICODE(#char1) is null then '' else concat(#char1,' - (',UNICODE(#char1),')') end,
case when UNICODE(#char2) is null then '' else concat(#char2,' - (',UNICODE(#char2),')') end,
case when ISNULL(UNICODE(#char1),0) <> isnull(UNICODE(#char2),0) then 'CHECK' else 'OK' END
)
set #i+=1
END
Select * from #diff_table
Declare #diff int = (Select count(*) from #diff_table where Status = 'Check')
Select #diff 'Difference'
The output will be like this:
I have a test function which would sanitize phone nos and allow only nos and characters "x" or "X" to be stored. I have it to where it does most of it other than it allows multiple x's which I don't want. Can anybody help me add it to the regular expression also let me know if you spot potential issues ?
CREATE Function [dbo].[RemoveAlphaCharacters](#Temp VarChar(1000))
Returns VarChar(1000)
AS
Begin
While PatIndex('%[^0-9,x,X]%', #Temp) > 0
Set #Temp = Stuff(#Temp, PatIndex('%[^0-9,x,X]%', #Temp), 1, '')
Return #TEmp
End
The problem with PATINDEX here is that it can't really determine that the pattern should change after it hits a string for the first time. So maybe this approach will be simpler:
CREATE FUNCTION [dbo].[RemoveAlphaCharacters]
(
#Temp VARCHAR(1000)
)
RETURNS VARCHAR(1000)
AS
BEGIN
DECLARE #i INT, #hitX BIT, #t VARCHAR(1000), #c CHAR(1);
SELECT #i = 1, #hitX = 0, #t = '';
WHILE #i <= LEN(#Temp)
BEGIN
SET #c = SUBSTRING(#Temp, #i, 1);
IF LOWER(#c) = 'x' AND #hitX = 0
BEGIN
SET #t = #t + #c;
SET #hitX = 1;
END
IF #c LIKE '[0-9]'
BEGIN
SET #t = #t + #c;
END
SET #i = #i + 1;
END
RETURN(#t);
END
GO
SELECT dbo.RemoveAlphaCharacters('401-867-9092');
SELECT dbo.RemoveAlphaCharacters('401-867-9092x32');
SELECT dbo.RemoveAlphaCharacters('401-867-9092x32x54');
Results:
4018679092
4018679092x32
4018679092x3254
How to check upper case existence length in a string using Sql Query?
For Eg:
1.KKart - from this string the result should be 2, because it has 2 upper case letters.
2.WPOaaa - from this string the result should be 3, because it has 3 upper case letters.
Thanks in advance
There is no built-in T-SQL function for that.
You can use a user-defined function like this one:
CREATE FUNCTION CountUpperCase
(
#input nvarchar(50)
)
RETURNS int
AS
BEGIN
declare #len int
declare #i int
declare #count int
declare #ascii int
set #len = len(#input)
set #i = 1
set #count = 0
while #i <= #len
begin
set #ascii = ascii(substring(#input, #i, 1))
if #ascii >= 65 and #ascii <= 90
begin
set #count = #count +1
end
set #i = #i + 1
end
return #count
END
Usage (with the examples from your question):
select dbo.CountUpperCase('KKart') returns 2.
select dbo.CountUpperCase('WPOaaa') returns 3.
How about something like this :
SELECT len(replace(my_string_field,'abcdefghijklmnopqrstuvwxyz','')) as 'UpperLen'
FROM my_table
The principle is simply to replace all lower case char by nothing and counts the remaining.