How Can I Preserve Order of Values from a Subquery in MySQL's IN() Clause?

Sort by value in SQL IN() clause

When dealing with queries involving multiple SELECT statements and IN() clauses, maintaining the order of values ​​in the first query can be a challenge in subsequent queries. This problem is encountered when the user wishes to retrieve specific information based on a predetermined sequence of IDs collected from the initial query.

A commonly adopted solution involves creating a temporary table with an auto-increment field and joining it with a second query. However, there is a simpler and more efficient option using MySQL's FIELD() function.

The FIELD() function accepts a list of values ​​as its second argument and returns the index of the first value that matches the first argument. By incorporating the FIELD() function into the ORDER BY clause of the second query, you can explicitly specify the desired order of results based on the values ​​in the IN() clause.

Consider the following example:

<code class="language-sql">SELECT name, description, ...
FROM ...
WHERE id IN([ids, any order])
ORDER BY FIELD(id, [ids in order])</code>

In this query, the FIELD() function aligns the values ​​in the id column with the desired order specified in the [ids in order] parameter. By using this technique, you can maintain the order of the values ​​in the first query in the second query without using temporary tables or complex subqueries. This approach not only simplifies your code but also improves its performance.

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