Stairway to Advanced T-SQL Level 10: Using Scalar Functions
Learn about scalar user defined functions in this next level in the Stairway.
2020-10-21 (first published: 2020-10-08)
3,589 reads
Gregory Larsen
2020-06-23
845 reads
2020-06-22
489 reads
2020-06-01
693 reads
2020-05-28
659 reads
Stairway to T-SQL DML Level 5: The Mathematics of SQL: Part 2
Joining tables is a crucial concept to understanding data relationships in a relational database. When you are working with your SQL Server data, you will often need to join tables to produce the results your application requires. Having a good understanding of set theory, and the mathematical operators available and how they are used to join tables will make it easier for you to retrieve the data you need from SQL Server.
2019-05-29 (first published: 2011-11-30)
18,186 reads
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.
2019-05-22 (first published: 2011-11-16)
24,510 reads
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)
20,538 reads
Stairway to T-SQL DML Level 12: Using the MERGE Statement
The final level of this stairway looks at the MERGE statement in detail, focusing on how to perform insert, update and delete logic using the MERGE statement.
2019-03-26 (first published: 2013-01-16)
21,658 reads
Stairway to T-SQL DML Level 3: Implementing a Relational Model in SQL Server
This level of the stairway details the creation of a relational database, as well as filling in some of the history of the relational database model.
2019-03-26 (first published: 2011-11-09)
18,144 reads
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Question of the Day
The Maximum Value in the Identity Column
I have a table with this data:
TravelLogID CityID StartDate EndDate 1 1 2025-01-01 2025-01-06 2 2 2025-01-01 2025-01-06 3 3 2025-01-01 2025-01-06 4 4 2025-01-01 2025-01-06 5 5 2025-01-01 2025-01-06I run this code:
SELECT IDENT_CURRENT('TravelLog')
I get the value 5 back. Now I do this:
SET IDENTITY_INSERT dbo.TravelLog ON
INSERT dbo.TravelLog
(
TravelLogID,
CityID,
StartDate,
EndDate
)
VALUES
(25, 5, '2025-09-12', '2025-09-17')
SET IDENTITY_INSERT dbo.TravelLog OFF
I now run this code.
DBCC CHECKIDENT(TravelLog)
GO
INSERT dbo.TravelLog
(
CityID,
StartDate,
EndDate
)
VALUES
(4, '2025-10-14', '2025-10-17')
GO
What is the value for TravelLogID for the row I inserted for CityID 4 and dates starting on 14 Oct 2025?
See possible answers