How Can I Count Rows Based on Conditions Within the COUNT() Function?

Conditional Row Counting within COUNT(): A Concise Approach

Often, you need to count rows meeting specific criteria. For example, counting only "Manager" entries in a "Position" column. Instead of using a WHERE clause, you can integrate the condition directly into the COUNT() function.

The Solution: CASE Statements and Aggregate Functions

The key is to remember that COUNT() only counts non-NULL values. Therefore, use a CASE statement like this:

SELECT COUNT(CASE Position WHEN 'Manager' THEN 1 ELSE NULL END)
FROM ...

Alternatively, you can use SUM() in a similar fashion:

SELECT SUM(CASE Position WHEN 'Manager' THEN 1 ELSE 0 END)
FROM ...

This approach allows conditional row counting within the COUNT() or SUM() function, avoiding the need for a separate WHERE clause, resulting in more compact and efficient SQL.

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