fix: allow multiple distinct columns on single shards (#10047)

Signed-off-by: Andres Taylor <[email protected]> Signed-off-by: Florent Poinsard <[email protected]> Co-authored-by: Andres Taylor <[email protected]>
vitessio · Apr 7, 2022 · 8750c6f · 8750c6f
1 parent 4e12193
commit 8750c6f
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diff --git a/go/vt/vtgate/planbuilder/testdata/aggr_cases.txt b/go/vt/vtgate/planbuilder/testdata/aggr_cases.txt
@@ -3116,3 +3116,25 @@ Gen4 plan same as above
     ]
   }
 }
+
+"select count(distinct user_id, name) from unsharded"
+{
+  "QueryType": "SELECT",
+  "Original": "select count(distinct user_id, name) from unsharded",
+  "Instructions": {
+    "OperatorType": "Route",
+    "Variant": "Unsharded",
+    "Keyspace": {
+      "Name": "main",
+      "Sharded": false
+    },
+    "FieldQuery": "select count(distinct user_id, `name`) from unsharded where 1 != 1",
+    "Query": "select count(distinct user_id, `name`) from unsharded",
+    "Table": "unsharded"
+  }
+}
+Gen4 plan same as above
+
+"select count(distinct user_id, name) from user"
+"unsupported: only one expression allowed inside aggregates: count(distinct user_id, `name`)"
+Gen4 error: aggregate functions take a single argument 'count(distinct user_id, `name`)'
diff --git a/go/vt/vtgate/semantics/analyzer.go b/go/vt/vtgate/semantics/analyzer.go
@@ -289,7 +289,7 @@ func (a *analyzer) checkForInvalidConstructs(cursor *sqlparser.Cursor) error {
 
 		if node.Distinct {
 			err := vterrors.Errorf(vtrpcpb.Code_INVALID_ARGUMENT, "syntax error: %s", sqlparser.String(node))
-			if len(node.Exprs) != 1 {
+			if len(node.Exprs) < 1 {
 				return err
 			} else if _, ok := node.Exprs[0].(*sqlparser.AliasedExpr); !ok {
 				return err