How to Retrieve Multiple Columns from a MySQL Subquery: Virtual Tables vs JOIN Syntax?

Selecting Multiple Columns from a MySQL Subquery

In MySQL, it can be challenging to retrieve multiple columns from the same table using a subquery. To address this issue, let's explore different approaches:

Using a Virtual Table

Instead of creating multiple subqueries, you can create a virtual table using a subquery. The syntax for this approach is:

SELECT *
FROM (SELECT col1, col2, ... FROM original_table) AS virtual_table

By using this virtual table in a join, you can retrieve multiple columns from the specified table in a single query.

Code Example:

SELECT a.attr, b.id, b.trans, b.lang
FROM attribute a
JOIN (
  SELECT id, translation AS trans, language AS lang, attribute
  FROM attributeTranslation
) AS b ON (a.id = b.attribute AND b.lang = 1)

Using JOIN Syntax

Another option is to use the JOIN syntax to combine multiple tables, including the original table and the virtual table. This approach allows you to retrieve multiple columns from the joined tables.

Code Example:

SELECT a.attr, b.id, b.trans, b.lang
FROM attribute a
JOIN attributeTranslation b ON (a.id = b.attribute AND b.lang = 1)

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