How Can I Efficiently Select Data from a Subquery Using Laravel's Query Builder?

Subquery selection in Laravel query builder

When using Eloquent ORM and Laravel query builder, you may encounter scenarios where you need to retrieve data based on a subquery. This question explores how to efficiently use the Laravel query builder to select data from a subquery.

Original question

As mentioned in the provided code example, the initial approach is to use multiple query builders to create and execute subqueries. However, users seek simpler and more effective solutions.

Improved solution

The best solution is not to use multiple chained query builders, but to use raw SQL statements in the FROM clause. This allows you to express subqueries directly in Laravel queries:

$sql = Abc::where(...)->groupBy(...)->toSql();
$num = DB::table(DB::raw("($sql) AS sub"))->count();
print $num;

Primitive subquery and binding considerations

Although this solution effectively selects data from a subquery, it is important to consider the following:

• Query Binding: When using raw SQL, you need to remember to incorporate the bindings of the Eloquent query builder into the raw SQL statement. This ensures that all parameters are bound correctly.
• Binding Merge Order: Be sure to merge bindings in the correct order. If additional binding clauses exist, they must be added after merging the subquery bindings.

Conclusion

The improved solution provides a simpler and more efficient way to select data from a subquery using the Laravel query builder. By including raw SQL in the FROM clause and handling query binding carefully, you can achieve the desired data retrieval concisely and efficiently.

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