T-SQL.co.uk - Hot questions

test questio test

Wed, 18 Jun 2025 10:03:16 +0000

[Application Status]

,[BISnumber]

,[AccountNumber]

,[Token]

,[Status]

,[FacilityTypeDescription]

,[Key]

,[Account_no]

,[Account_type]

,[Customer_no]

,[EFS ACCOUNT KEY]

,[Check]

Mask Numbers

Wed, 21 May 2025 00:26:42 +0000

CREATE FUNCTION dbo.MaskCreditCardLike_12_18 (

@input NVARCHAR(MAX)

)

RETURNS NVARCHAR(MAX)

BEGIN

DECLARE @output NVARCHAR(MAX) = @input;

DECLARE @i INT = 1;

DECLARE @digitCount INT = 0;

DECLARE @startPos INT = 0;

WHILE @i <= LEN(@input)

BEGIN

DECLARE @c NCHAR(1) = SUBSTRING(@input, @i, 1);

IF @c LIKE '[0-9]'

BEGIN

IF @digitCount = 0

SET @startPos = @i;

SET @digitCount += 1;

END

ELSE IF @c IN ('-', '/', '*', 'X', 'x', ' ')

BEGIN

-- allowed separator, do not reset

CONTINUE;

END

ELSE

BEGIN

-- invalid char, reset

SET @digitCount = 0;

SET @startPos = 0;

END

-- Once we hit a 12- to 18-digit count, replace the original segment

IF @digitCount BETWEEN 12 AND 18

BEGIN

-- Now find the end of the segment

DECLARE @endPos INT = @i;

WHILE @endPos + 1 <= LEN(@input) AND

SUBSTRING(@input, @endPos + 1, 1) IN ('0','1','2','3','4','5','6','7','8','9','-','/','*','X','x',' ')

BEGIN

SET @endPos += 1;

END

DECLARE @replaceLength INT = @endPos - @startPos + 1;

SET @output = STUFF(@output, @startPos, @replaceLength, '$');

RETURN @output;

END

SET @i += 1;

END

RETURN @output;

END;

CREATE FUNCTION dbo.ReplaceCodePattern (

@input NVARCHAR(MAX)

)

RETURNS NVARCHAR(MAX)

BEGIN

DECLARE @output NVARCHAR(MAX) = @input;

DECLARE @start INT;

DECLARE @length INT;

-- Try 499

SET @start = PATINDEX('%499%****%', @output);

IF @start > 0

BEGIN

SET @length = CHARINDEX('****', @output, @start) + 3 - @start + 1;

RETURN STUFF(@output, @start, @length, '$');

END

-- Try 540

SET @start = PATINDEX('%540%****%', @output);

IF @start > 0

BEGIN

SET @length = CHARINDEX('****', @output, @start) + 3 - @start + 1;

RETURN STUFF(@output, @start, @length, '$');

END

-- Try 543

SET @start = PATINDEX('%543%****%', @output);

IF @start > 0

BEGIN

SET @length = CHARINDEX('****', @output, @start) + 3 - @start + 1;

RETURN STUFF(@output, @start, @length, '$');

END

RETURN @output;

END;

CREATE FUNCTION dbo.ReplaceCodePattern_Exclude16Digit (

@input NVARCHAR(MAX)

)

RETURNS NVARCHAR(MAX)

BEGIN

DECLARE @output NVARCHAR(MAX) = @input;

DECLARE @cleaned NVARCHAR(MAX);

-- Clean string: remove -, /, *, X, space

SET @cleaned = REPLACE(@input, '-', '');

SET @cleaned = REPLACE(@cleaned, '/', '');

SET @cleaned = REPLACE(@cleaned, '*', '');

SET @cleaned = REPLACE(@cleaned, 'X', '');

SET @cleaned = REPLACE(@cleaned, ' ', '');

-- Check for any 16-digit numeric substring

IF PATINDEX('%[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]%', @cleaned) > 0

BEGIN

RETURN @input; -- skip replacement

END

-- Attempt match on 499

DECLARE @start INT = PATINDEX('%499%****%', @output);

IF @start > 0

BEGIN

DECLARE @length INT = CHARINDEX('****', @output, @start) + 3 - @start + 1;

RETURN STUFF(@output, @start, @length, '$');

END

-- Attempt match on 540

SET @start = PATINDEX('%540%****%', @output);

IF @start > 0

BEGIN

SET @length = CHARINDEX('****', @output, @start) + 3 - @start + 1;

RETURN STUFF(@output, @start, @length, '$');

END

-- Attempt match on 543

SET @start = PATINDEX('%543%****%', @output);

IF @start > 0

BEGIN

SET @length = CHARINDEX('****', @output, @start) + 3 - @start + 1;

RETURN STUFF(@output, @start, @length, '$');

END

RETURN @output;

END;

CREATE FUNCTION dbo.MaskCreditCardLike (

@input NVARCHAR(MAX)

)

RETURNS NVARCHAR(MAX)

BEGIN

DECLARE @output NVARCHAR(MAX) = @input;

DECLARE @normalized NVARCHAR(MAX);

-- Clean input to only digits

SET @normalized = REPLACE(@input, '-', '');

SET @normalized = REPLACE(@normalized, '/', '');

SET @normalized = REPLACE(@normalized, '*', '');

SET @normalized = REPLACE(@normalized, 'X', '');

SET @normalized = REPLACE(@normalized, 'x', '');

SET @normalized = REPLACE(@normalized, ' ', '');

-- If no 16-digit sequence exists, return original

IF PATINDEX('%[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]%', @normalized) = 0

RETURN @input;

-- Naive scan for the 16-digit run in original

DECLARE @i INT = 1;

DECLARE @countDigits INT = 0;

DECLARE @startPos INT = 0;

WHILE @i <= LEN(@input)

BEGIN

IF SUBSTRING(@input, @i, 1) LIKE '[0-9]'

BEGIN

SET @countDigits = @countDigits + 1;

IF @countDigits = 16

BEGIN

SET @startPos = @i - 15;

-- Replace the range with a $

SET @output = STUFF(@output, @startPos, 16, '$');

RETURN @output;

END

ELSE IF CHARINDEX(SUBSTRING(@input, @i, 1), '-/*Xx ') > 0

BEGIN

-- allow formatting chars

CONTINUE;

END

ELSE

BEGIN

-- reset if invalid char

SET @countDigits = 0;

END

SET @i = @i + 1;

END

RETURN @output;

END;

Get Only Numbers from String

Wed, 14 May 2025 09:48:35 +0000

CREATE FUNCTION dbo.fn_KeepOnlyNumbers (@input NVARCHAR(MAX))

RETURNS NVARCHAR(MAX)

BEGIN

WHILE PATINDEX('%[^0-9]%', @input) > 0

BEGIN

SET @input = STUFF(@input, PATINDEX('%[^0-9]%', @input), 1, '')

END

RETURN @input

END

Usage:

SELECT dbo.fn_KeepOnlyNumbers('A1B2C-3D_4E!5F') AS OnlyNumbers

How do I check for CC Numbers

Wed, 14 May 2025 08:47:00 +0000

CREATE FUNCTION dbo.fn_ValidateCreditCard

(

@CardNumber VARCHAR(25)

)

RETURNS TABLE

RETURN

WITH Cleaned AS (

SELECT

REPLACE(REPLACE(@CardNumber, ' ', ''), '-', '') AS CleanCard

LuhnCheck AS (

SELECT

CleanCard,

LEN(CleanCard) AS CardLength,

REVERSE(CleanCard) AS ReversedCard

FROM Cleaned

Calculated AS (

SELECT

CleanCard,

CardLength,

SUM(

CASE

WHEN Number % 2 = 0 THEN Digit

ELSE

CASE

WHEN Digit * 2 > 9 THEN Digit * 2 - 9

ELSE Digit * 2

END

) AS LuhnSum

FROM (

SELECT

CleanCard,

CardLength,

Digit = CAST(SUBSTRING(ReversedCard, Number + 1, 1) AS INT),

Number

FROM LuhnCheck

JOIN master.dbo.spt_values ON type = 'P' AND Number BETWEEN 0 AND LEN(ReversedCard) - 1

) AS Digits

GROUP BY CleanCard, CardLength

IssuerCheck AS (

SELECT

CleanCard,

CardLength,

CASE

WHEN CleanCard LIKE '4%' AND (CardLength = 13 OR CardLength = 16 OR CardLength = 19) THEN 'Visa'

WHEN CleanCard LIKE '5[1-5]%' AND CardLength = 16 THEN 'MasterCard'

WHEN CleanCard LIKE '222[1-9]%' OR CleanCard LIKE '22[3-9][0-9]%'

OR CleanCard LIKE '2[3-6][0-9][0-9]%' OR CleanCard LIKE '27[01][0-9]%'

OR CleanCard LIKE '2720%' AND CardLength = 16 THEN 'MasterCard'

WHEN CleanCard LIKE '3[47]%' AND CardLength = 15 THEN 'American Express'

WHEN CleanCard LIKE '6011%' OR CleanCard LIKE '65%' OR CleanCard LIKE '64[4-9]%'

AND CardLength = 16 THEN 'Discover'

ELSE 'Unknown'

END AS Issuer

FROM Calculated

Final AS (

SELECT

c.CleanCard AS CardNumber,

i.Issuer,

CASE WHEN c.LuhnSum % 10 = 0 THEN 1 ELSE 0 END AS IsValid

FROM Calculated c

JOIN IssuerCheck i ON c.CleanCard = i.CleanCard

)

SELECT * FROM Final;

Example Usage:

SELECT dbo.fn_IsValidCreditCardNumber('4539 1488 0343 6467') AS IsValid; -- Returns 1

SELECT dbo.fn_IsValidCreditCardNumber('1234 5678 9012 3456') AS IsValid; -- Returns 0

I have rtf text converted to blob stored in a SQL field, and I need to search the text content of it.

Fri, 19 Aug 2022 12:56:26 +0000

I have loads of .rtf files, which are stored in a SQL blob, in a field/Column in my database.

How can I search for text within this document without converting all docs back in to their respective .rtf format.

How Should I Store Currency Values in SQL Server?

Fri, 26 Jun 2020 08:24:48 +0000

Never ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever store currency as a float in your database.

I completely agree with this statement. Never store values used in financial calculations as floating point values, because a floating point is an approximate representation of a decimal value, stored as binary. In most cases it is inaccurate as soon as you store it. You can read more in this excellent - if a little dry - technical paper.

With that out of the way, we get into an interesting discussion about the correct data type to store currency values.

MONEY and SMALLMONEY. I like to think I know a little bit about picking the right data type for a certain column.

So I was surprised when a friend on that Twitter thread mentioned that he stores currency values as integers (multiplying them by 100 first). Being as literal as I am, I thought he meant the INTEGER (or INT) data type, which is a four-byte data type that goes up to around 2.1 billion (for values greater than zero), but Michael reminded me that "big integers exist," so of course my friend was talking about BIGINT.

I wrote in a reply that "Decimal will have to do. I'm not going to store money as a BIGINT." Nevertheless, I found it an interesting thought experiment to write about here.

Assume that your currency has a hundred possible decimal values from 0.00 to 0.99. Now assume that you can eliminate pesky rounding errors by storing currency data in cents as a BIGINT. This requires you to multiply the currency amount by 100 when inserting it, and dividing by 100 when displaying it. That seems counterproductive in my mind, but bear with me as we investigate this further.

What problem is this meant to solve? Why avoid the use of the DECIMAL data type, which is engineered to store decimal values with a decimal precision? Is the risk of rounding errors so great as to avoid a data type completely as the floating point? Surely DECIMAL can handle this? Most of the time we use simple sums ( SUM), averages ( AVG), and regular arithmetic operations like addition, subtraction, multiplication and division, and in my experience - provided I put the parentheses in the right place - I've never run into a rounding error that was significant enough (i.e. outside of the tolerance of the organization calculating the amounts) to be a problem.

As I've pointed out before, BIGINT ranges from negative 9 quintillion, to positive 9 quintillion (a number that is 19 digits wide). That's a lot of squillions. Even storing these values as cents, you can store amounts that could handle even the ill-fated Zimbabwean dollar, which - at the time it was discontinued - was distributed in $100-trillion notes (100,000,000,000,000.00, or 17 digits wide). A BIGINT needs 8 bytes of uncompressed storage for each value.

Now DECIMAL is a different beastie. If you need the highest precision, a DECIMAL can use up to 17 bytes for each value. Generally though, I like using DECIMAL(19,4) for currency, which needs 9 bytes and can store numbers 19 digits wide, where the last four digits are after the decimal place. Coincidentally, this has the same range of values as the MONEY data type. Maybe it's not a coincidence that I chose that then, eh?

Purists will say that the MONEY data type is woefully inaccurate when it comes to calculations, including multiplication and division. To those purists I say "pish!" Unless we're talking Bitcoin, a currency amount usually has two decimal places. By using four decimal places, this means that rounding errors are less likely. In the vast majority of cases you will be doing things like summing values, calculating percentages,

Select Block Mode of Text

Tue, 19 May 2020 11:54:03 +0000

I want to be able to select from my SSMS window text in a block like in textpad. Is there an add on for this?

How Do I change Date and Time Conversions Type

Wed, 26 Feb 2020 16:11:11 +0000

What are JOINs in SQL, and what types of JOINs are there?

Wed, 26 Feb 2020 15:40:11 +0000

What is the difference between DELETE and TRUNCATE statements?

Wed, 26 Feb 2020 15:26:59 +0000

What is SQL?

Wed, 26 Feb 2020 15:33:37 +0000

What are SQL constraints?

Wed, 26 Feb 2020 15:41:19 +0000

What is a DBMS?

Wed, 26 Feb 2020 15:37:10 +0000

What are the different clauses used in SQL?

Wed, 26 Feb 2020 15:38:34 +0000

What are tables in SQL?

Wed, 26 Feb 2020 15:37:52 +0000

How can I get the DATE in SQL with English Suffix Eg 21st

Wed, 19 Feb 2020 11:53:35 +0000

I want to be able to pull back the DATE from SQL which displays in the format " Day Name Date Number + Suffix Month Year