TEIID-5471 correcting the behavior of string_agg over no values

# Conflicts: # engine/src/test/java/org/teiid/query/processor/TestWindowFunctions.java
teiid · Sep 11, 2018 · 476be5b · 476be5b
1 parent 2629baf
commit 476be5b
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Showing 2 changed files with 17 additions and 1 deletion.
diff --git a/engine/src/main/java/org/teiid/query/function/aggregate/StringAgg.java b/engine/src/main/java/org/teiid/query/function/aggregate/StringAgg.java
@@ -121,7 +121,7 @@ private void writeValue(Object val) throws TeiidProcessingException {
      */
     public Object getResult(CommandContext commandContext) throws TeiidProcessingException{
     	if (this.result == null) {
-    		this.result = buildResult(commandContext);
+    		return null;
     	}
 
     	try {

diff --git a/engine/src/test/java/org/teiid/query/processor/TestAggregateProcessing.java b/engine/src/test/java/org/teiid/query/processor/TestAggregateProcessing.java
@@ -966,6 +966,22 @@ private FunctionMethod addAgg(Schema s, String name, Class<?> clazz, String retu
 		helpProcess(plan, dataManager, expected);
 	}
 
+	@Test public void testStringAggNoRows() throws Exception {
+        // Create query
+        String sql = "SELECT string_agg(e1, ',') from pm1.g1 where e2 > 10"; //$NON-NLS-1$
+
+        // Create expected results
+        List[] expected = new List[] {
+                Collections.singletonList(null),
+        };
+
+        FakeDataManager dataManager = new FakeDataManager();
+        sampleData1(dataManager);
+
+        ProcessorPlan plan = helpGetPlan(sql, RealMetadataFactory.example1Cached(), TestAggregatePushdown.getAggregatesFinder());
+        helpProcess(plan, dataManager, expected);
+    }
+
 	@Test public void testStringAggBinary() throws Exception {
 		// Create query
 		String sql = "SELECT cast(string_agg(to_bytes(e1, 'UTF-8'), X'AB') as varbinary) from pm1.g1 group by e3"; //$NON-NLS-1$