[BugFix] Fix union isnullable error (#32426)

Signed-off-by: Seaven <[email protected]> (cherry picked from commit c39da42)
StarRocks · Oct 11, 2023 · 92bd7cd · 92bd7cd
1 parent 6a13b59
commit 92bd7cd
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Showing 2 changed files with 25 additions and 2 deletions.
diff --git a/fe/fe-core/src/main/java/com/starrocks/sql/plan/PlanFragmentBuilder.java b/fe/fe-core/src/main/java/com/starrocks/sql/plan/PlanFragmentBuilder.java
@@ -2578,9 +2578,16 @@ private PlanFragment buildSetOperation(OptExpression optExpr, ExecPlan context,
             // reset column is nullable, for handle union select xx join select xxx...
             setOperationNode.setHasNullableGenerateChild();
             List<Expr> setOutputList = Lists.newArrayList();
-            for (ColumnRefOperator columnRefOperator : setOperation.getOutputColumnRefOp()) {
+            for (int index = 0; index < setOperation.getOutputColumnRefOp().size(); index++) {
+                ColumnRefOperator columnRefOperator = setOperation.getOutputColumnRefOp().get(index);
                 SlotDescriptor slotDesc = context.getDescTbl().getSlotDesc(new SlotId(columnRefOperator.getId()));
-                slotDesc.setIsNullable(slotDesc.getIsNullable() | setOperationNode.isHasNullableGenerateChild());
+                boolean isNullable = slotDesc.getIsNullable() | setOperationNode.isHasNullableGenerateChild();
+                for (List<ColumnRefOperator> childOutputColumn : setOperation.getChildOutputColumns()) {
+                    ColumnRefOperator childRef = childOutputColumn.get(index);
+                    Expr childExpr = ScalarOperatorToExpr.buildExecExpression(childRef, formatterContext);
+                    isNullable |= childExpr.isNullable();
+                }
+                slotDesc.setIsNullable(isNullable);
                 setOutputList.add(new SlotRef(String.valueOf(columnRefOperator.getId()), slotDesc));
             }
             setOperationTuple.computeMemLayout();

diff --git a/fe/fe-core/src/test/java/com/starrocks/sql/plan/EmptyValueTest.java b/fe/fe-core/src/test/java/com/starrocks/sql/plan/EmptyValueTest.java
@@ -178,4 +178,20 @@ public void testOther() throws Exception {
                 "  |  \n" +
                 "  1:EMPTYSET");
     }
+
+    @Test
+    public void testUnionSlot() throws Exception {
+        String sql = "select L_ORDERKEY " +
+                "from t0 left outer join lineitem_partition on L_ORDERKEY = t0.v2 and L_SHIPDATE = '2000-01-01' " +
+                "union all " +
+                "select L_ORDERKEY " +
+                "from t0 left outer join lineitem_partition on L_ORDERKEY = t0.v2 and L_SHIPDATE = '2000-01-01' ";
+        String plan = getVerboseExplain(sql);
+        assertContains(plan, "  0:UNION\n" +
+                "  |  output exprs:\n" +
+                "  |      [41, INT, true]\n" +
+                "  |  child exprs:\n" +
+                "  |      [4: L_ORDERKEY, INT, true]\n" +
+                "  |      [24: L_ORDERKEY, INT, true]");
+    }
 }