Stairway to T-SQL DML

Stairway to T-SQL DML Level 4: The Mathematics of SQL: Part 1

A relational database contains tables that relate to each other by key values. When querying data from these related tables you may choose to select data from a single table or many tables. If you select data from many tables, you normally join those tables together using specified join criteria. The concepts of selecting data from tables and joining tables together is all about managing and manipulating sets of data. In Level 4 of this Stairway we will explore the concepts of set theory and mathematical operators to join, merge, and return data from multiple SQL Server tables.

Blogs

Measuring RAG Solutions: Are We Retrieving the Right Information?

By

A RAG pipeline that answers questions in the demo is not the same thing...

Advice I Like: Lots of Ideas

By

“A multitude of bad ideas is necessary for one good idea” – from Excellent...

Building a DBA Agent for Your SQL Server Estate with MCP

By

Yesterday I gave a talk for MSSQLTips called “Building a DBA Agent for Your...

Read the latest Blogs

Forums

Adding new column with DEFAULT

By Thomas Franz

Comments posted to this topic are about the item Adding new column with DEFAULT

How do I connect to a SQL Server database on my ISP?

By Doctor Who 2

I've got a web application for my side business. I've added a SQL Server...

Looking for New Blood

By Grant Fritchey

Comments posted to this topic are about the item Looking for New Blood

Visit the forum

Question of the Day

Adding new column with DEFAULT

Which number will the COUNT() return after executing the following statements:

DROP TABLE IF EXISTS #test;
CREATE TABLE #test (id INT)
INSERT INTO #test (id)
SELECT *
  FROM GENERATE_SERIES(1, 3) AS gs
;

ALTER TABLE #test ADD flag BIT CONSTRAINT DF_#test_flag DEFAULT 0;
go
UPDATE #test SET flag = 0 WHERE id = 1
UPDATE #test SET flag = 1 WHERE id = 2

INSERT INTO #test (id) VALUES (4)

SELECT COUNT(*)
  FROM #test AS t
 WHERE flag = 0
 

See possible answers