2024-12-06
637 reads
Subquery
Three Use Case Examples for SQL Subqueries
There are many great tutorials on syntax, performance, and keywords for invoking subqueries. However, I wish to discover a tip highlighting selected SQL subquery use cases. Please briefly describe three SQL subquery use case examples. For each use case, cover how a subquery interacts with outer queries and the T-SQL for implementing the use case. Review excerpts from each example to show the value of implementing the use case.
2023-04-14
2019-11-08
1,150 reads
SQL Server Subquery in Select Statement with Where Clause
In this part of the temporary data store tip series we look at using subqueries to select data as well as how to use for inserts, updates and deletes.
2019-05-22
Stairway to T-SQL: Beyond The Basics Level 3: Building a Correlated Subquery
This stairway level will expand on the subquery topic by discussing a type of subquery known as a correlated subquery, and explores what a correlated subquery is and how it is different from a normal subquery.
2019-05-08 (first published: 2014-03-05)
20,683 reads
2013-05-09
2,253 reads
2013-03-08
2,372 reads
2013-01-11
2,727 reads
2011-09-19
3,144 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) + 1Which of the following queries produces the expected ordering and why? (Select all correct) See possible answers