Fix handling of joins with filter containing correlated joins

In a query like:

    SELECT
        n.nspname AS schema,
        t.typname AS typename,
        t.oid::int4 AS typeid
    FROM
        pg_type t
        LEFT JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace
    WHERE
        EXISTS (SELECT 1 FROM pg_catalog.pg_type el WHERE el.oid = t.typelem);

The filter `EXISTS (SELECT 1 FROM pg_catalog.pg_type el WHERE el.oid =
t.typelem)` was placed in-between correlated-join and join:

    └ CorrelatedJoin[typname, oid, typnamespace, typelem, nspname, oid, (SELECT 1 FROM (el))] (rows=0)
      └ Filter[EXISTS (SELECT 1 FROM (el))] (rows=0)
        └ NestedLoopJoin[LEFT | (oid = typnamespace)] (rows=unknown)

Given that the filter uses the output of the `CorrelatedJoin`, that led
to an error:

    Couldn't create execution plan from logical plan because of: Couldn't find (SELECT 1 FROM (el)) in SourceSymbols

The filter must be placed above the correlated join, not below.

Fixes #14671

docs/appendices/release-notes/5.4.5.rst

@@ -46,6 +46,21 @@ See the :ref:`version_5.4.0` release notes for a full list of changes in the
 Fixes
 =====
 
+- Fixed an issue that led to ``Couldn't create execution plan from logical plan
+  ..`` errors when trying to use a correlated join in the ``WHERE`` clause of a
+  query with a join. For example::
+
+    SELECT
+        n.nspname AS schema,
+        t.typname AS typename,
+        t.oid::int4 AS typeid
+    FROM
+        pg_type t
+        LEFT JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace
+    WHERE
+        EXISTS (
+            SELECT 1 FROM pg_catalog.pg_type el WHERE el.oid = t.typelem);
+
 - Fixed an issue that prevented namespaces from showing up in
   ``pg_catalog.pg_namespace`` if a user had privileges on a table within a
   schema, but no privileges on the schema itself.

server/src/main/java/io/crate/planner/operators/JoinPlanBuilder.java

@@ -142,11 +142,11 @@ static LogicalPlan buildJoinTree(List<AnalyzedRelation> from,
             );
             joinNames.add(nextRel.relationName());
         }
+        joinPlan = subQueries.applyCorrelatedJoin(joinPlan);
         if (!queryParts.isEmpty()) {
             joinPlan = Filter.create(joinPlan, AndOperator.join(queryParts.values()));
             queryParts.clear();
         }
-        joinPlan = subQueries.applyCorrelatedJoin(joinPlan);
         joinPlan = Filter.create(joinPlan, AndOperator.join(correlatedSubQueriesFromJoin.correlatedSubQueries()));
         joinPlan = Filter.create(joinPlan, AndOperator.join(correlatedSubQueriesFromWhereClause.correlatedSubQueries()));
         assert joinPairsByRelations.isEmpty() : "Must've applied all joinPairs";

server/src/test/java/io/crate/integrationtests/CorrelatedSubqueryITest.java

@@ -429,4 +429,23 @@ public void test_can_use_column_in_query_paired_with_correlation_that_is_not_sel
             assertThat(result.getInt(1)).isEqualTo(1);
         }
     }
+
+    @Test
+    public void test_correlated_subquery_together_with_join() throws Exception {
+        // https://github.com/crate/crate/issues/14671
+        execute(
+            """
+            SELECT
+                n.nspname AS schema,
+                t.typname AS typename,
+                t.oid::int4 AS typeid
+            FROM
+                pg_type t
+                LEFT JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace
+            WHERE
+                EXISTS (
+                    SELECT 1 FROM pg_catalog.pg_type el WHERE el.oid = t.typelem);
+            """);
+        assertThat(response).hasRowCount(24L);
+    }
 }