Split words with a capital letter in sql

Does anyone know how to split words starting with capital letters from a string?

Example:

    DECLARE @var1 varchar(100) = 'OneTwoThreeFour'
    DECLARE @var2 varchar(100) = 'OneTwoThreeFourFive'
    DECLARE @var3 varchar(100) = 'One'

    SELECT @var1 as Col1, <?> as Col2
    SELECT @var2 as Col1, <?> as Col2
    SELECT @var3 as Col1, <?> as Col2

expected result:

    Col1                Col2
    OneTwoThreeFour     One Two three Four
    OneTwoThreeFourFive One Two Three Four Five
    One                 One

If this is not possible (or if too long) an scalar function would be okay as well.

Here is a function I created that is similar to the "removing non-alphabetic characters". How to strip all non-alphabetic characters from string in SQL Server?

This one uses a case sensitive collation which actively seeks out a non-space/capital letter combination and then uses the STUFF function to insert the space. This IS a scalar UDF, so some folks will immediately say that it will be slower than other solutions. To that notion, I say, please test it. This function does not use any table data and only loops as many times as necessary, so it will likely give you very good performance.

Create Function dbo.Split_On_Upper_Case(@Temp VarChar(1000))
Returns VarChar(1000)
AS
Begin

    Declare @KeepValues as varchar(50)
    Set @KeepValues = '%[^ ][A-Z]%'
    While PatIndex(@KeepValues collate Latin1_General_Bin, @Temp) > 0
        Set @Temp = Stuff(@Temp, PatIndex(@KeepValues collate Latin1_General_Bin, @Temp) + 1, 0, ' ')

    Return @Temp
End

Call it like this:

Select dbo.Split_On_Upper_Case('OneTwoThreeFour')
Select dbo.Split_On_Upper_Case('OneTwoThreeFour')
Select dbo.Split_On_Upper_Case('One')
Select dbo.Split_On_Upper_Case('OneTwoThree')
Select dbo.Split_On_Upper_Case('stackOverFlow')
Select dbo.Split_On_Upper_Case('StackOverFlow')

Here is a function I have just created.

FUNCTION

CREATE FUNCTION dbo.Split_On_Upper_Case
 (
     @String VARCHAR(4000)
 )
RETURNS VARCHAR(4000)
AS
BEGIN

DECLARE @Char CHAR(1);
DECLARE @i    INT = 0;
DECLARE @OutString VARCHAR(4000) = '';


WHILE (@i <= LEN(@String))
BEGIN
    SELECT @Char = SUBSTRING(@String, @i,1)

    IF (@Char = UPPER(@Char) Collate Latin1_General_CS_AI) 
       SET @OutString = @OutString + ' ' + @Char;
    ELSE 
       SET @OutString = @OutString +  @Char;

     SET @i += 1;
END

 SET @OutString =  LTRIM(@OutString);

 RETURN @OutString;

END

Test Data

DECLARE @TABLE TABLE (Strings VARCHAR(1000))
INSERT INTO @TABLE 
VALUES ('OneTwoThree')   ,
       ('FourFiveSix')   ,
       ('SevenEightNine')

Query

SELECT dbo.Split_On_Upper_Case(Strings) AS Vals
FROM @TABLE

Result Set

╔══════════════════╗
║       Vals       ║
╠══════════════════╣
║ One Two Three    ║
║ Four Five Six    ║
║ Seven Eight Nine ║
╚══════════════════╝

Build a Numbers table. There are some excellent posts on SO to show you how to do this. Populate it with values up the maximum length of your input string. Select the values from 1 through the actual length of the current input string. Cross join this list of numbers to the input string. Use the result to SUBSTRING() each character. Then you can either compare the resulting list of one-charachter values to a pre-populated table-valued variable or convert each character to an integer using ASCII() and choose only those between 65 ('A') and 90 ('Z'). At this point you have a list which is the position of each upper-case character in your input string. UNION the maximum length of your input string onto the end of this list. You'll see why in just a second. Now you can SUBSTRING() your input variable, starting at the Number given by row N and taking a length of (the Number given by row N+1) - (The number given by row N). This is why you have to UNION the extra Number on the end. Finally concatenate all these substring together, space-separated, using the algorithm of your choice.

Sorry, don't have an instance in front of me to try out code. Sounds like a fun task. I think doing it with nested SELECT statements will get convoluted and un-maintainable; better to lay it out as CTEs, IMHO.

Split words with a capital letter in sql

Related

Recent Posts