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Manage Your Business Rules in T-SQL Query

Motivation At some point in the carrer, we have come across the problem of hard-coded values in SELECT or WHERE clauses.  And we all agree that these hardcoded values must be parametrised. This bad habit usually backfires when we need to troubleshoot a query. These hardcoded values are usually a business role baked in the […]

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Finding the Version of a Flyway-managed Database Using SQL

Maintaining a version of a database opens a lot of possibilities, especially if an automated process can easily grab the current version, at runtime, using just SQL. You might, for example, have a routine that is only appropriate after a particular version. It is also very handy to be able to associate entries in an event log or bug report with the database version. No more desultory quests, when dealing with support issues, or when bug fixing, to find which database version was running when the bug happened.

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By Steve Jones - SSC Editor

Comments posted to this topic are about the item What's New for the Microsoft...

Using Outer Joins

By Steve Jones - SSC Editor

Comments posted to this topic are about the item Using Outer Joins

Closest to ProcDate

By boehnc

Not sure I have this 2nd left join correct. I need to grab the...

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Question of the Day

Using Outer Joins

I have this data in a SQL Server 2019 database:

Customer table
CustomerID CustomerName
1          Steve
2          Andy
3          Brian
4          Allen
5          Devin
6          Sally

OrderHeader table
OrderID CustomerID OrderDate
1       1          2024-02-01
2       1          2024-03-01
3       3          2024-04-01
4       4          2024-05-01
6       4          2024-05-01
7       3          2024-06-07
8       2          2024-04-07
I want a list of all customers and their order counts for a period of time, including zero orders. If I run this query, how many rows are returned?
SELECT 
  c.CustomerName, COUNT(oh.OrderID)
 FROM dbo.Customer AS c
LEFT JOIN dbo.OrderHeader AS oh ON oh.CustomerID = c.CustomerID
WHERE oh.Orderdate > '2024/04/01'
GROUP BY c.CustomerName

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