On my last article - What happens when we drop a column on a SQL Server table? Where’s my space? - I have shown what happens when we drop a column from a table. Today, we are going to check if we have a way to find tables with dropped columns. Why? As we learnt, when we drop a column this is just a metadata operation and won’t clear the space that was being used.

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This article was initially posted on SQLServerCentral @ 2024-04-26. Short answer: The column is marked as ‘deleted’ and will stop being visible/usable. But, most importantly - The record/table size will remain unchanged. A metadata operation Dropping a column is a metadata/logical operation, not a physical one. This means that the data isn’t removed/overwritten by this action. As Paul Randal mentions here : “the cost of that will be deferred for the inserters and not for the deleters”.

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A couple of days ago I was doing some cleaning on some Azure SQL DBs and shrinking some files to lower the bill. To check my progress I needed to check the size before/after the task in an easy way for multiple Azure SQL DBs. Check Azure SQL DB storage space for 1 database If you need to check the storage space being used by 1 Azure SQL DB, that is as easy as jumping on the portal, select the desired database and you can find the information in the Overview.

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Today I will write just a short blog post to do a quick reminder! I still hear a lot of people suggesting CTEs because they think it works like a temporary table (you populate the table and then it can be/is reutilized). It doesn’t! From de documentation : Specifies a temporary named result set, known as a common table expression (CTE). Maybe they are focusing on the “temporary” word. Using the CTE two times will perform two different executions!

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