How to Pivot a T-SQL Table Without Using Aggregate Functions?

T-SQL Pivot: No Aggregation Functions Needed

In some cases, you may need to convert data in a table to pivot format without using aggregate functions such as SUM or COUNT. This example shows a unique way to use the PIVOT operator when aggregate functions are not required.

Suppose there is a source table containing customer information:

CustomerID	DBColumnName	Data
1	FirstName	Joe
1	MiddleName	S
1	LastName	Smith
1	Date	12/12/2009
2	FirstName	Sam
2	MiddleName	S
2	LastName	Freddrick
2	Date	1/12/2009
3	FirstName	Jaime
3	MiddleName	S
3	LastName	Carol
3	Date	12/1/2009

The target output is a pivot table showing customer information in separate columns:

CustomerID	FirstName	MiddleName	LastName	Date
1	Joe	S	Smith	12/12/2009
2	Sam	S	Freddrick	1/12/2009
3	Jaime	S	Carol	12/1/2009

To achieve this without using aggregate functions, you can use the following T-SQL query:

<code class="language-sql">SELECT CustomerID,
       MIN(CASE DBColumnName WHEN 'FirstName' THEN Data END) AS FirstName,
       MIN(CASE DBColumnName WHEN 'MiddleName' THEN Data END) AS MiddleName,
       MIN(CASE DBColumnName WHEN 'LastName' THEN Data END) AS LastName,
       MIN(CASE DBColumnName WHEN 'Date' THEN Data END) AS Date
  FROM table
 GROUP BY CustomerId;</code>

This query uses the MIN function in a CASE statement to select the minimum value for each column based on DBColumnName. The "GROUP BY" clause is used to group the results by CustomerID.

While this approach may appear unwieldy and inefficient compared to using aggregate functions, it can provide greater flexibility in certain situations where aggregate functions are not appropriate (such as when dealing with unique or distinct values) sex. Be sure to evaluate the specific needs of your query and choose the most appropriate approach for the given situation.

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