[SPARK-40615][SQL] Check unsupported data types when decorrelating subqueries

core/src/main/resources/error/error-classes.json

@@ -879,6 +879,11 @@
           "Expressions referencing the outer query are not supported outside of WHERE/HAVING clauses<treeNode>"
         ]
       },
+      "UNSUPPORTED_CORRELATED_REFERENCE_DATA_TYPE" : {
+        "message" : [
+          "Correlated column reference '<expr>' cannot be <dataType> type"
+        ]
+      },
       "UNSUPPORTED_CORRELATED_SCALAR_SUBQUERY" : {
         "message" : [
           "Correlated scalar subqueries can only be used in filters, aggregations, projections, and UPDATE/MERGE/DELETE commands<treeNode>"
@@ -3133,4 +3138,4 @@
       "<className> must override either <m1> or <m2>"
     ]
   }
-}
+}

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/DecorrelateInnerQuery.scala

@@ -19,12 +19,13 @@ package org.apache.spark.sql.catalyst.optimizer
 
 import scala.collection.mutable.ArrayBuffer
 
+import org.apache.spark.SparkException
 import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.expressions.SubExprUtils._
 import org.apache.spark.sql.catalyst.plans._
 import org.apache.spark.sql.catalyst.plans.logical._
 import org.apache.spark.sql.catalyst.trees.TreePattern.OUTER_REFERENCE
-import org.apache.spark.sql.errors.QueryExecutionErrors
+import org.apache.spark.sql.errors.{QueryCompilationErrors, QueryExecutionErrors}
 import org.apache.spark.util.collection.Utils
 
 /**
@@ -360,7 +361,20 @@ object DecorrelateInnerQuery extends PredicateHelper {
           //                        +- Aggregate [a1] [a1 AS a']
           //                           +- OuterQuery
           val conditions = outerReferenceMap.map {
-            case (o, a) => EqualNullSafe(a, OuterReference(o))
+            case (o, a) =>
+              val cond = EqualNullSafe(a, OuterReference(o))
+              // SPARK-40615: Certain data types (e.g. MapType) do not support ordering, so
+              // the EqualNullSafe join condition can become unresolved.
+              if (!cond.resolved) {
+                if (!RowOrdering.isOrderable(a.dataType)) {
+                  throw QueryCompilationErrors.unsupportedCorrelatedReferenceDataTypeError(
+                    o, a.dataType, plan.origin)
+                } else {
+                  throw SparkException.internalError(s"Unable to decorrelate subquery: " +
+                    s"join condition '${cond.sql}' cannot be resolved.")
+                }
+              }
+              cond
           }
           (domainJoin, conditions.toSeq, AttributeMap(outerReferenceMap))
         }

sql/catalyst/src/main/scala/org/apache/spark/sql/errors/QueryCompilationErrors.scala

@@ -1944,6 +1944,17 @@ private[sql] object QueryCompilationErrors extends QueryErrorsBase {
       messageParameters = Map("function" -> funcStr))
   }
 
+  def unsupportedCorrelatedReferenceDataTypeError(
+      expr: Expression,
+      dataType: DataType,
+      origin: Origin): Throwable = {
+    new AnalysisException(
+      errorClass = "UNSUPPORTED_SUBQUERY_EXPRESSION_CATEGORY." +
+        "UNSUPPORTED_CORRELATED_REFERENCE_DATA_TYPE",
+      origin = origin,
+      messageParameters = Map("expr" -> expr.sql, "dataType" -> dataType.typeName))
+  }
+
   def functionCannotProcessInputError(
       unbound: UnboundFunction,
       arguments: Seq[Expression],

sql/core/src/test/scala/org/apache/spark/sql/SubquerySuite.scala

@@ -2336,4 +2336,30 @@ class SubquerySuite extends QueryTest
       checkAnswer(sql("select(select sum((select sum(col) from t)) from t)"), Row(null))
     }
   }
+
+  test("SPARK-40615: Check unsupported data type when decorrelating subqueries") {
+    withTempView("v1", "v2") {
+      sql(
+        """
+          |create temp view v1(x) as values
+          |from_json('{"a":1, "b":2}', 'map<string,int>') t(x)
+          |""".stripMargin)
+      sql(
+        """
+          |create temp view v2(x) as values
+          |from_json('{"b":0, "c":2}', 'map<string,int>') t(x)
+          |""".stripMargin)
+
+      // Can use non-orderable data type in one row subquery that can be collapsed.
+      checkAnswer(
+        sql("select (select a + a from (select x['a'] as a)) from v1"),
+        Row(2))
+
+      // Cannot use non-orderable data type in one row subquery that cannot be collapsed.
+      val error = intercept[AnalysisException] {
+        sql("select (select a + a from (select upper(x['a']) as a)) from v1").collect()
+      }
+      assert(error.getMessage.contains("Correlated column reference 'v1.x' cannot be map type"))
+    }
+  }
 }