Missing Data
When we don't have all the information needed to model data, we often use NULL. However, that causes other issues.
2021-04-12
2,818 reads
Joe Celko
Mathematicians and SQL
Georg Ferdinand Ludwig Philipp Cantor is considered the creator of set theory, and his theories are the basis for the naïve set theory you learned in school. But there are lots of other mathematicians you should know, such as Hilbert, Frege, Russell, Zermelo and Dedekind. They made a lot of contributions, too. Hilbert Hilbert is […]
2021-01-19
5,701 reads
Data Element Names and Scoping Rules in SQL
How you name data elements in databases and applications programs has often been a matter of personal taste. Decades ago, when I worked for state government, there is a COBOL programmer who would pick a theme for his programs. The paragraphs and variables would be named based on the current theme. One of his programs […]
2021-01-11
2,230 reads
Stairway to Database Design Level 8: Cursors
This final level to the first landing completes the basics of a SQL database, by explaining what cursors are and why you should never use them.
2020-11-18 (first published: 2011-11-02)
11,843 reads
2020-10-12
2,029 reads
Stairway to Data, Level 4: Temporal Data
Joe Celko tackles the most difficult of all the types of data handled by SQL, temporal data, and explains how to avoid the commonest traps for the unwary programmer
2020-07-08 (first published: 2011-06-15)
11,327 reads
Stairway to Database Design Level 6: Procedure Bodies
Having covered the procedure headers in SQL Server in the previous level, Joe tackles the subject of the contents of stored procedures. In this level, he outlines limitations of TSQL as a procedural language, and what you need to bear in mind when deciding how to use them.
2019-04-03 (first published: 2011-09-21)
13,655 reads
Stairway to Data, Level 1: The Basics
A great deal of the confusion that occurs when a database application is developed comes from a poor understanding of the basics of data. Here, Joe Celko gives a broad coverage of the difficulties you're likely to meet when handling data in databases.
2019-02-06 (first published: 2011-05-12)
20,835 reads
Stairway to Database Design Level 9: Normalization
In the final step of Database Design, Joe Celko gives a simple but effective explanation of the normalization process and why it is important.
2018-02-21 (first published: 2011-11-11)
15,839 reads
Stairway to Database Design Level 7: Triggers
In levels one to four, we built the tables, base and virtual, of a schema. Levels five and six dealt with stored procedures. This level deals with a feature you need to avoid as much as possible; this is article is on Triggers.
2018-01-24 (first published: 2011-09-30)
12,511 reads
Blogs
The SUM of Nothing: #SQLNewBlogger
By Steve Jones
I caught this interesting item over on Pinal Dave’s blog: Eleven Interview Questions that...
How to Move the SSMS Status Bar to the Top and Color-Code SQL Server Connections
By Hemantgiri
I use color-coded connections in SSMS to distinguish Production, Pre-Production, UAT, and Development. But...
Forums
Split Large Queries in Athena with a Simple Modulo Trick
Comments posted to this topic are about the item Split Large Queries in Athena...
Finding Trailing Spaces
Comments posted to this topic are about the item Finding Trailing Spaces
Question of the Day
Finding Trailing Spaces
I have some data in a SQL Server 2025 database. It looks like this for the dbo.Customer table:
CustomerID CustomerName PreferredName 1 Steve Steve 2 Andy Andy 3 Brian Brian 4 Allan Allan 5 Devin Devin 6 Steve Steve 7 Sally SallyI want to detect which names have a single trailing space. The CustomerName is a varchar() and the PreferredName is a CHAR(). Does this query detect the problem rows?
SELECT
CustomerID,
CustomerName,
PreferredName
FROM Customer
WHERE CustomerName <> RTRIM(CustomerName)
OR PreferredName <> RTRIM(PreferredName); See possible answers