Rotate a table in SQL Server

This article describes how to rotate a table in SQL Server.

Original product version:   SQL Server
Original KB number:   175574

Summary

This article describes how to rotate a SQL Server table. Suppose you have a table that is named QTRSALES. The table has the columns YEAR, QUARTER, and AMOUNT with the data in the following format.

Now, suppose you want to rotate the table so that you can see the data in the following format:

The query that you would use to rotate the table is in the next section of this article.

Sample query to rotate the table

Here's the query that you would use to rotate the table:

SELECT YEAR,
Q1= ISNULL((SELECT AMOUNT FROM QTRSALES WHERE QUARTER = 1 AND YEAR =
Q.YEAR),0),
Q2= ISNULL((SELECT AMOUNT FROM QTRSALES WHERE QUARTER = 2 AND YEAR =
Q.YEAR),0),
Q3= ISNULL((SELECT AMOUNT FROM QTRSALES WHERE QUARTER = 3 AND YEAR =
Q.YEAR),0),
Q4= ISNULL((SELECT AMOUNT FROM QTRSALES WHERE QUARTER = 4 AND YEAR =
Q.YEAR),0)
FROM QTRSALES Q
GROUP BY YEAR

Query for large tables

For large tables, this query will be faster:

SELECT YEAR,
SUM(CASE quarter WHEN 1 THEN amount ELSE 0 END) AS Q1,
SUM(CASE quarter WHEN 2 THEN amount ELSE 0 END) AS Q2,
SUM(CASE quarter WHEN 3 THEN amount ELSE 0 END) AS Q3,
SUM(CASE quarter WHEN 4 THEN amount ELSE 0 END) AS Q4
FROM qtrsales q
GROUP BY YEAR

Reference

FROM - Using PIVOT and UNPIVOT