How Can I Pivot Data Using SQL Server 2000?

Pivot Data with SQL Server 2000

The need to transform data into a pivoted format, where values are placed in columns instead of rows, often arises in data analysis. SQL Server 2000 provides a straightforward solution for this task.

Problem Description

Consider two tables: Products and Product Meta. The Products table contains product attributes, while the Product Meta table stores metadata related to each product. The goal is to generate a result set that pivots the data, displaying product names as rows and metadata values as columns.

Solution

To achieve this, follow these steps:

1. Create a GROUP BY Statement: Group the data by the ProductId and Name columns. This step ensures that only unique product rows are represented in the result set.
2. Aggregate Metadata Values: For each grouped row, aggregate the metadata values using the MIN() or MAX() function, depending on the desired behavior. In this case, MIN() is used to select the minimum value for each metadata key.
3. Alias Aggregate Functions: Assign meaningful aliases to the aggregate functions to represent the column headers in the pivoted result set. For instance, if the metadata keys were 'A', 'B', and 'C', the aggregate functions could be aliased as 'A', 'B', and 'C' respectively.

The resulting query would look similar to the following:

SELECT P.ProductId, P.Name
    , MIN(CASE WHEN PM.MetaKey = 'A' THEN PM.MetaValue END) AS A
    , MIN(CASE WHEN PM.MetaKey = 'B' THEN PM.MetaValue END) AS B
    , MIN(CASE WHEN PM.MetaKey = 'C' THEN PM.MetaValue END) AS C
FROM Products AS P
JOIN ProductMeta AS PM
    ON PM.ProductId = P.ProductId
GROUP BY P.ProductId, P.Name

This query will produce the desired pivoted result set, where each row represents a product, and each column displays the corresponding metadata value.

By following these steps, you can effectively pivot data using SQL Server 2000, enabling you to gain insights from your data in a more structured and user-friendly format.

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