2009-10-28
3,945 reads
T-SQL
2009-10-26
4,502 reads
2009-10-21
5,087 reads
2009-10-19
3,634 reads
Causation, Correlation and Crackpots
Joe Celko explores the dangers of muddling correlation and causation, emphasises the importance of determining how likely it is that a correlation has occurred by chance, and gets stuck into calculating correlation coefficients in SQL. Along the way, Joe illustrates the consequences of leaping to the wrong conclusion from correlations with tales of Pop Dread.
2009-10-19
2,136 reads
2009-10-16
5,102 reads
2009-10-14
4,697 reads
Concatenating Rows
Often in database design we store different values in rows to take advantage of a normalized design. However many times we need to combine multiple rows of data into one row for a report of some sort. New author Carl P. Anderson brings us some interesting T-SQL code to accomplish this.
2011-03-04 (first published: 2009-10-14)
150,384 reads
SQL and the JOIN Operator
How the JOIN operator works, the different types of JOINs and relevant information about joining tables.
2011-03-03 (first published: 2009-10-07)
47,588 reads
Retrieve consecutive records from the table based the value difference
Retrieve consecutive records from the table based the value difference
2009-11-04 (first published: 2009-10-06)
946 reads
Blogs
T-SQL Tuesday #192: What career risks have you taken?
By James Serra
I’m honored to be hosting T-SQL Tuesday — edition #192. For those who may...
AI: Blog a Day – Day 3: LLM Models – Open Source vs Closed Source
By Vinay Thakur
Continuing from Day 2 , we learned introduction on Generative AI and Agentic AI,...
How to Parameterize Fabric Linked Services in Azure Data Factory for Azure Devops Deployment
Quite the title, so let me set the stage first. You have an Azure...
Forums
how to write this query?
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Rollback vs. Roll Forward
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Foreign Keys - Foes or Friend?
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Question of the Day
Fun with JSON I
I have some data in a table:
CREATE TABLE #test_data
(
id INT PRIMARY KEY,
name VARCHAR(100),
birth_date DATE
);
-- Step 2: Insert rows
INSERT INTO #test_data
VALUES
(1, 'Olivia', '2025-01-05'),
(2, 'Emma', '2025-03-02'),
(3, 'Liam', '2025-11-15'),
(4, 'Noah', '2025-12-22');
If I run this query, how many rows are returned?
SELECT *
FROM OPENJSON(
(
SELECT t.* FROM #test_data AS t FOR JSON PATH
)
) t; See possible answers