How Can I Pivot a MySQL Entity-Attribute-Value (EAV) Schema for Tabular Data Output?

Pivoting MySQL Entity-Attribute-Value Schema

In database design, an entity-attribute-value schema (EAV) is commonly used to store metadata for entities with a variable number of custom attributes. This approach allows for flexibility in defining new attributes without modifying the database schema. However, querying EAV data in a tabular format can be challenging.

Problem:

You have MySQL tables that store the metadata for files using an EAV schema:

• FileBase: Common metadata (name, author, created)
• Attributes: Custom attribute names and types
• FileAttributes: Attribute values for files

You need to query the data to display it in a tabular format, where each row represents a file and each custom attribute has its own column.

Solution:

MySQL provides the GROUP_CONCAT() function to concatenate multiple values into a single string. This function can be used to aggregate attribute values for each file and create a comma-separated list of attributes. Here's a query to achieve this:

SELECT
  bt.FileID,

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