Return the merged data using the alias

Since we return an error if the same series has more than one alias this
fixes #270

datastore/shard.go

@@ -134,9 +134,13 @@ func (self *Shard) executeMergeQuery(querySpec *parser.QuerySpec, processor engi
 			log.Error(err)
 			return err
 		}
+		aliases := querySpec.SelectQuery().GetTableAliases(s.Name)
+		if len(aliases) > 1 {
+			return fmt.Errorf("Cannot have the same table joined more than once")
+		}
 		streams[i] = PointIteratorStream{
 			pi:     iterators[i],
-			name:   s.Name,
+			name:   aliases[0],
 			fields: c,
 		}
 		i++

integration/data_test.go

@@ -1182,6 +1182,24 @@ func (self *DataTestSuite) TestWhereConditionWithExpression(c *C) {
 	c.Assert(maps[0]["b"], Equals, 1.0)
 }
 
+func (self *DataTestSuite) JoinedWithSelf(c *C) (Fun, Fun) {
+	return func(client Client) {
+			client.WriteJsonData(`
+[
+  {
+    "name": "t",
+    "columns": ["time", "value"],
+    "points":[
+		  [1381346706000, 3],
+		  [1381346701000, 1]
+	  ]
+  }
+]`, c, influxdb.Millisecond)
+		}, func(client Client) {
+			client.RunInvalidQuery("select * from t as foo inner join t as bar", c, "m")
+		}
+}
+
 // issue #740 and #781
 func (self *DataTestSuite) TestJoiningDifferentFields(c *C) {
 	// TODO: why do we get a different error if we remove all but the first values

integration/legacy_data_test.go

@@ -1649,32 +1649,6 @@ func (self *DataTestSuite) QueryWithJoinedTablesWithWhereClause(c *C) (Fun, Fun)
 		}
 }
 
-func (self *DataTestSuite) JoinedWithSelf(c *C) (Fun, Fun) {
-	return func(client Client) {
-			createEngine(client, c, `[
-    {
-      "points": [
-        { "values": [{ "int64_value": 3 }], "timestamp": 1381346706000000 },
-        { "values": [{ "int64_value": 1 }], "timestamp": 1381346701000000 }
-      ],
-      "name": "t",
-      "fields": ["value"]
-    }
-  ]`)
-		}, func(client Client) {
-			runQuery(client, "select * from t as foo inner join t as bar", c, `[
-    {
-      "points": [
-        { "values": [{ "int64_value": 3 }, { "int64_value": 3 }], "timestamp": 1381346706000000 },
-        { "values": [{ "int64_value": 1 }, { "int64_value": 1 }], "timestamp": 1381346701000000 }
-      ],
-      "name": "foo_join_bar",
-      "fields": ["foo.value", "bar.value"]
-    }
-  ]`)
-		}
-}
-
 func (self *DataTestSuite) QueryWithMergedTablesWithPointsAppend(c *C) (Fun, Fun) {
 	return func(client Client) {
 			createEngine(client, c, `[