Reverse Statement Word by Word in SQL server
Last Updated :
01 Oct, 2020
To reverse any statement Word by Word in SQL server we could use the SUBSTRING function which allows us to extract and display the part of a string.
Pre-requisite :SUBSTRING function
Approach :
- Declared three variables (@Input, @Output, @Length) using the DECLARE statement.
- Use the WHILE Loop to iterate every character present in the @Input. For the condition inside the SQL Server while loop, use the SQL LEN Function to check whether the length of the Input is greater than 0 or not.
- Within the while loop, use the SUBSTRING Function to set the @Output value with three parameters, and they are Input, start point, endpoint. Here we assigned the Input as @Input, use the start point as 0.
- Use the CHARINDEX Function to find the ‘ ‘, so that the endpoint will be before the space.
- Now, adding this to @Output, and which is empty at the starting of the loop.
- To update the @Input variable, use the SUBSTRING Function. Here we assigned the Input as @Input.
- Next, use the SQL CHARINDEX Function to find the empty space, and then we added 1 so that the starting point will be after space.
- Then, use the SQL LEN Function to specify the end value.
- At SET @Output it is extracting the word starting at 0 indexes and up to empty space. That will be the first word.
- Once it got its first word, it will remove that word from @Input using the SET @Input code.
Input :
Welcome to SQL Server Tutorial on Geeksforgeeks.
Example –
DECLARE @Input VARCHAR(MAX)
DECLARE @Output VARCHAR(MAX)
DECLARE @Length INT
SET @Input = 'Welcome to SQL Server
Tutorial on Geeksforgeeks.'
SET @Output = ''
WHILE LEN(@Input) > 0
BEGIN
IF CHARINDEX(' ', @Input) > 0
BEGIN
SET @Output = SUBSTRING
(@Input, 0, CHARINDEX(' ', @Input))
+ ' ' + @Output
SET @Input = LTRIM
(RTRIM
(SUBSTRING
(@Input, CHARINDEX
(' ', @Input) + 1, LEN(@Input))))
END
ELSE
BEGIN
SET @Output = @Input + ' ' + @Output
SET @Input = ''
END
END
SELECT @Output
Output :
Geeksforgeeks. on Tutorial Server SQL to Welcome
Input and Output using SQL Server Management Studio :
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