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Try Before You Commit in Flyway

Sometimes we want to check whether it is possible to run a Flyway migration without error, but not actually make the changes. We might just need to 'sanity test' the performance of a migration on the Staging server, for example. By using a placeholder 'switch' to trigger a SQL Exception, we can get Flyway to roll-back its transaction, and therefore the migration, on demand.

Stairway to SQL Server Indexes

Deeper into Nonclustered Indexes: Stairway to SQL Server Indexes Level 2

By this stage, you should be familiar with the basics of SQL Server indexes. We've discussed what an Index actually is, as well as some of the most common types you're likely to encounter. Now that we've seen some simple examples of how Indexes can be useful, we're going to delve deeper into nonclustered indexes, as we'll see how they can improve the performance of more complex queries.

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By Steve Jones - SSC Editor

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Using Outer Joins

By Steve Jones - SSC Editor

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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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