From 32b5826d1afb118c5dcd67943d10ebadc6c0283f Mon Sep 17 00:00:00 2001
From: Travis <travis@pilosa.com>
Date: Fri, 28 Aug 2020 16:53:42 -0500
Subject: [PATCH] fix bug on left/right join mapping

---
 server/grpc_test.go | 40 ++++++++++++++++++++++++++++++++++++++++
 sql/extract.go      |  4 ++--
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/server/grpc_test.go b/server/grpc_test.go
index f3521f1e9..1b5cc415e 100644
--- a/server/grpc_test.go
+++ b/server/grpc_test.go
@@ -755,6 +755,46 @@ func TestQuerySQLUnary(t *testing.T) {
 			},
 			eq: equal,
 		},
+		// The following cases test different paths within the `case *sqlparser.AndExpr`
+		// of extract.go by providing different WHERE conditions.
+		{
+			// len(left) == 2 && len(right) == 1
+			// right[0].table == left[0].table
+			sql: "select _id from grouper g INNER JOIN joiner j ON g._id = j.grouperid where g.color = 'red' and j.jointype = 2 and g.age = 16",
+			exp: tableResponse{
+				headers: []columnInfo{{"_id", "uint64"}},
+				rows: []row{
+					{[]columnResponse{uint64(8)}},
+					{[]columnResponse{uint64(9)}},
+				},
+			},
+			eq: equalUnordered,
+		},
+		{
+			// len(left) == 2 && len(right) == 1
+			// right[0].table == left[1].table {
+			sql: "select _id from grouper g INNER JOIN joiner j ON g._id = j.grouperid where j.jointype = 2 and g.color = 'red' and g.age = 16",
+			exp: tableResponse{
+				headers: []columnInfo{{"_id", "uint64"}},
+				rows: []row{
+					{[]columnResponse{uint64(8)}},
+					{[]columnResponse{uint64(9)}},
+				},
+			},
+			eq: equalUnordered,
+		},
+		{
+			// len(left) == 1 && len(right) == 1 && left[0].table != right[0].table
+			sql: "select _id from grouper g INNER JOIN joiner j ON g._id = j.grouperid where g.color = 'red' and g.age = 16 and j.jointype = 2",
+			exp: tableResponse{
+				headers: []columnInfo{{"_id", "uint64"}},
+				rows: []row{
+					{[]columnResponse{uint64(8)}},
+					{[]columnResponse{uint64(9)}},
+				},
+			},
+			eq: equalUnordered,
+		},
 	}
 
 	for i, test := range tests {
diff --git a/sql/extract.go b/sql/extract.go
index 464d69383..419811efa 100644
--- a/sql/extract.go
+++ b/sql/extract.go
@@ -1042,12 +1042,12 @@ func extractWheres(indexes []*pilosa.Index, tbls parseTables, expr sqlparser.Exp
 				return []*tableWhere{left[0], right[0]}, nil
 			}
 			return nil, errors.Errorf("no matching table on right: %s", left[0].table.name)
-		} else if len(left) == 1 && len(right) == 2 {
+		} else if len(left) == 2 && len(right) == 1 {
 			// if left(2) and right(1),
 			// then intersect the 1's and return final(2)
 			if right[0].table == left[0].table {
 				right[0].where = Intersect(right[0].where, left[0].where)
-				return []*tableWhere{left[0], right[1]}, nil
+				return []*tableWhere{left[1], right[0]}, nil
 			} else if right[0].table == left[1].table {
 				right[0].where = Intersect(right[0].where, left[1].where)
 				return []*tableWhere{left[0], right[0]}, nil