No running through SubQueries #69
Description
I have the problem that with SubQueries, the traversing stops.
var ast = new Parser().ParseSql(sql, new PostgreSqlDialect(), new ParserOptions()
{
RecursionLimit = 20000
});
var visitor = new PostgresVisitor(allowedType);
ast.Visit(visitor);Here an example sql query:
SELECT *
FROM ds_customers c
LEFT JOIN LATERAL (
SELECT *
FROM ds_orders o
WHERE o.customer_id = c.id
ORDER BY o.order_date DESC
LIMIT 3
) recent_orders ON true;I am trying to collect all the tables called up. I have built a hotfix that checks if there is a SubQuery and runs it again. I can use it for reading. I also have a “ReplaceVisitor” which replaces table names. I can't get that to work. It would be great if the SubQuery could simply continue to be used normally like the main query. Am I doing something wrong here?
public override ControlFlow PreVisitTableFactor(TableFactor relation)
{
// Handle TableFactor.Derived (for LATERAL JOINs and subqueries)
if (relation is TableFactor.Derived derived)
{
Console.WriteLine($"[VISITOR] Found TableFactor.Derived - Lateral: {derived.Lateral}");
if (derived.SubQuery != null)
{
Console.WriteLine($"[VISITOR] Derived has SubQuery - will let base visitor handle it");
Console.WriteLine($"[VISITOR] SubQuery type: {derived.SubQuery.GetType().Name}");
Console.WriteLine($"[VISITOR] SubQuery sql: {derived.SubQuery.ToSql()}");
PostgresVisitor visitor = new PostgresVisitor(AllowedType);
var ast = new Parser().ParseSql(derived.SubQuery.ToSql(), new PostgreSqlDialect(), new ParserOptions()
{
RecursionLimit = 20000
});
ast.Visit(this);
return ControlFlow.Continue;
}
// Let the base visitor handle the traversal
return base.PreVisitTableFactor(relation);
}
if (!(relation is TableFactor.Table))
return base.PreVisitTableFactor(relation);
var table = relation.AsTable();
Console.WriteLine($"[VISITOR] Found TableFactor.Table - Name: {table?.Name}");
if (table != null)
{
// logic for table
}
return base.PreVisitTableFactor(relation);
}Without the derived.SubQuery part, the SubQuery is never run.