How to Perform Conditional Counting in SQL Server Without COUNTIF?

SQL Server Conditional Counting: A CASE-Based Approach

Aggregate functions are essential for data analysis in SQL Server. While COUNT provides a total row count, conditional counting requires a different strategy. SQL Server lacks a direct COUNTIF equivalent, but we can achieve the same result using SUM and CASE.

Imagine needing to calculate the percentage of rows where MyColumn equals '1'. A naive attempt might look like this:

SELECT  UID, 
        COUNT(UID) AS TotalRecords, 
        SUM(ContractDollars) AS ContractDollars,
        (COUNTIF(MyColumn, 1) / COUNT(UID) * 100) -- Incorrect: COUNTIF not supported
FROM    dbo.AD_CurrentView
GROUP BY UID
HAVING  SUM(ContractDollars) >= 500000

The COUNTIF function is not a standard SQL Server function. The solution lies in leveraging SUM and CASE:

SELECT  UID, 
        COUNT(UID) AS TotalRecords, 
        SUM(ContractDollars) AS ContractDollars,
        (SUM(CASE WHEN MyColumn = 1 THEN 1 ELSE 0 END) / COUNT(UID) * 100) -- Correct conditional count
FROM    dbo.AD_CurrentView
GROUP BY UID
HAVING  SUM(ContractDollars) >= 500000

The CASE statement checks each row's MyColumn. If it's '1', it returns 1; otherwise, it returns 0. SUM then totals these 1s and 0s, effectively counting the occurrences of '1' in MyColumn. This provides an accurate conditional count, enabling precise calculations and insightful data analysis.

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