diff --git a/relational-query.cabal b/relational-query.cabal
--- a/relational-query.cabal
+++ b/relational-query.cabal
@@ -1,5 +1,5 @@
 name:                relational-query
-version:             0.3.0.3
+version:             0.3.0.4
 synopsis:            Typeful, Modular, Relational, algebraic query engine
 description:         This package contiains typeful relation structure and
                      relational-algebraic query building DSL which can
@@ -72,7 +72,7 @@
                        , text
                        , dlist
                        , template-haskell
-                       , sql-words
+                       , sql-words >=0.1.1
                        , names-th
                        , persistable-record
 
diff --git a/src/Database/Relational/Query/ProjectableExtended.hs b/src/Database/Relational/Query/ProjectableExtended.hs
--- a/src/Database/Relational/Query/ProjectableExtended.hs
+++ b/src/Database/Relational/Query/ProjectableExtended.hs
@@ -39,7 +39,6 @@
 
 import Prelude hiding (pi)
 import Data.Int (Int64)
-import Data.Monoid ((<>))
 
 import qualified Language.SQL.Keyword as SQL
 
@@ -67,7 +66,7 @@
 -- | Unsafely make aggregation uni-operator from SQL keyword.
 unsafeAggregateOp :: (AggregatedContext ac, SqlProjectable (p ac))
                   => SQL.Keyword -> Projection Flat a -> p ac b
-unsafeAggregateOp op = unsafeUniOp ((op <>) . SQL.paren)
+unsafeAggregateOp op = unsafeUniOp ((op SQL.<++>) . SQL.paren)
 
 -- | Aggregation function COUNT.
 count :: (AggregatedContext ac, SqlProjectable (p ac))