Joseph Gama


Technical Article

Find a string in Procedures, Triggers, etc

I want to thank James Travis for his original and excellent work and to Razvan Socol for alerting about a similar problem that led me to improve James' code. The problem is that when searching for a word that is split between two 8kb blocks, James' code would ignore it. The solution is to look […]

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2004-02-21

186 reads

Technical Article

UDF Luhn's formula-credit card number validation

This UDF will validate a credit card number using Luhn's formula.For example 49927398716 will return 1:print dbo.luhn('49927398716')print dbo.luhn(49927398716)11based on:Credit cards, validation and the Luhn formulabyEduardo Chaveshttp://www.webdevelopersjournal.com/articles/validation.htmlAlgorithm converted to TSQL by Joseph Gama

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2002-12-12

571 reads

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Question of the Day

ORDER BY alias

There is a table tmp_tab:

CREATE TABLE tmp_tab (
id int,
val int
);
INSERT INTO tmp_tab VALUES
(1, 1),
(2, NULL),
(3, 3),
(4, 4),
(5, 5);
You want to order the rows ids by the following expression:
    ISNULL(val, id) + 1
Which of the following queries produces the expected ordering and why? (Select all correct)

See possible answers