diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 # Revision history for seakale
 
+## 0.2.0.0  -- 2017-02-23
+
+* Fix a bug with conditions such as `col = NULL` instead of `col IS NULL`
+
 ## 0.1.0.0  -- 2017-01-31
 
 * First version.
diff --git a/seakale.cabal b/seakale.cabal
--- a/seakale.cabal
+++ b/seakale.cabal
@@ -1,5 +1,5 @@
 name:                  seakale
-version:               0.1.0.0
+version:               0.2.0.0
 synopsis:              Pure SQL layer on top of other libraries
 description:           This library allows you to write pure code doing operations on a SQL databases. It can therefore be tested by mocking the database with the package 'seakale-tests'. To run it of a specific database, you need another package such as 'seakale-postgresql'.
 license:               BSD3
@@ -14,7 +14,7 @@
 source-repository head
   type:                darcs
   location:            http://darcs.redspline.com/seakale
-  tag:                 0.1.0.0
+  tag:                 0.2.0.0
 
 library
   ghc-options:         -Wall
diff --git a/src/Database/Seakale/Store.hs b/src/Database/Seakale/Store.hs
--- a/src/Database/Seakale/Store.hs
+++ b/src/Database/Seakale/Store.hs
@@ -210,32 +210,32 @@
 (==.) :: (Property backend a f, ToRow backend n b) => f backend n b -> b
       -> Condition backend a
 (==.) prop vals =
-  buildCondition "=" (flip toColumns prop) (flip toRow vals)
+  buildCondition "=" "IS" (flip toColumns prop) (flip toRow vals)
 
 (/=.) :: (Property backend a f, ToRow backend n b) => f backend n b -> b
       -> Condition backend a
 (/=.) prop vals =
-  buildCondition "<>" (flip toColumns prop) (flip toRow vals)
+  buildCondition "<>" "IS NOT" (flip toColumns prop) (flip toRow vals)
 
 (<=.) :: (Property backend a f, ToRow backend n b) => f backend n b -> b
       -> Condition backend a
 (<=.) prop vals =
-  buildCondition "<=" (flip toColumns prop) (flip toRow vals)
+  buildCondition "<=" "<=" (flip toColumns prop) (flip toRow vals)
 
 (<.) :: (Property backend a f, ToRow backend n b) => f backend n b -> b
      -> Condition backend a
 (<.) prop vals =
-  buildCondition "<" (flip toColumns prop) (flip toRow vals)
+  buildCondition "<" "<" (flip toColumns prop) (flip toRow vals)
 
 (>=.) :: (Property backend a f, ToRow backend n b) => f backend n b -> b
       -> Condition backend a
 (>=.) prop vals =
-  buildCondition ">=" (flip toColumns prop) (flip toRow vals)
+  buildCondition ">=" ">=" (flip toColumns prop) (flip toRow vals)
 
 (>.) :: (Property backend a f, ToRow backend n b) => f backend n b -> b
      -> Condition backend a
 (>.) cols vals =
-  buildCondition ">" (flip toColumns cols) (flip toRow vals)
+  buildCondition ">" ">" (flip toColumns cols) (flip toRow vals)
 
 (==#) :: (Property backend a f, Property backend a g)
       => f backend n b -> g backend n b -> Condition backend a
@@ -328,9 +328,10 @@
   let step value (suffix, (Condition f)) =
         (", ",) $ Condition $ \prefix backend ->
           let (req, dat) = f prefix backend
-              valueList = mconcat $ intersperse ", " $ vectorToList $
-                            toRow backend value
-          in (Hole (Plain suffix req), Cons ("(" <> valueList <> ")") dat)
+              valueList = mconcat $ intersperse ", " $ map (fromMaybe "NULL") $
+                            vectorToList $ toRow backend value
+          in ( Hole (Plain suffix req)
+             , Cons (Just ("(" <> valueList <> ")")) dat )
 
       (_, cond) = foldr step ("", mempty) values
 
@@ -375,4 +376,4 @@
 (=.) :: (Property backend a f, ToRow backend n b)
      => f backend n b -> b -> UpdateSetter backend a
 (=.) col value = UpdateSetter $ \backend ->
-  vzip (toColumns backend col) (toRow backend value)
+  vzip (toColumns backend col) (fmap (fromMaybe "NULL") $ toRow backend value)
diff --git a/src/Database/Seakale/Store/Internal.hs b/src/Database/Seakale/Store/Internal.hs
--- a/src/Database/Seakale/Store/Internal.hs
+++ b/src/Database/Seakale/Store/Internal.hs
@@ -100,16 +100,21 @@
                    `qappend` Plain (" " <> op <> " ") (parenthesiseQuery q2)
     in (q, qdat1 `vappend` qdat2)
 
-buildCondition :: BS.ByteString -> (backend -> Vector n Column)
+buildCondition :: BS.ByteString -> BS.ByteString -> (backend -> Vector n Column)
                -> (backend -> QueryData n) -> Condition backend a
-buildCondition op vec dat =
+buildCondition op op' vec dat =
     Condition $ \prefix backend ->
-      (go id (fmap (($ prefix) . unColumn) (vec backend)), dat backend)
+      let dat' = dat backend
+          cols = fmap (($ prefix) . unColumn) (vec backend)
+          req  = go id cols dat'
+      in (req, dat')
   where
-    go :: (forall m. Query m -> Query m) -> Vector n BS.ByteString -> Query n
-    go _ Nil = EmptyQuery
-    go f (Cons x xs) =
-      f $ Plain (x <> " " <> op <> " ") $ Hole $ go (Plain " AND ") xs
+    go :: (forall m. Query m -> Query m) -> Vector n BS.ByteString
+       -> QueryData n -> Query n
+    go _ Nil Nil = EmptyQuery
+    go f (Cons x xs) (Cons mBS dat') =
+      f $ Plain (x <> " " <> maybe op' (const op) mBS <> " ") $
+            Hole $ go (Plain " AND ") xs dat'
 
 buildCondition' :: BS.ByteString
                 -> (backend -> Vector n Column) -> (backend -> Vector n Column)
diff --git a/src/Database/Seakale/ToRow.hs b/src/Database/Seakale/ToRow.hs
--- a/src/Database/Seakale/ToRow.hs
+++ b/src/Database/Seakale/ToRow.hs
@@ -106,7 +106,7 @@
   data ValueProxy con (K1 i a) b = ProxyConst (Maybe a)
   toValueProxy _ _ = ProxyConst . fmap unK1
   gtoRow backend _ = (,Nothing) . \case
-    ProxyConst Nothing  -> ntimes "NULL"
+    ProxyConst Nothing  -> ntimes Nothing
     ProxyConst (Just x) -> toRow backend x
 
 instance (Constructor c, GToRow backend con n a)
@@ -136,10 +136,10 @@
 instance ToRow backend Zero ()
 
 instance ToRow backend One Null where
-  toRow _ Null = ["NULL"]
+  toRow _ Null = [Nothing]
 
-formatString :: BS.ByteString -> BS.ByteString
-formatString str = "'" <> escapeQuotes "" str <> "'"
+formatString :: BS.ByteString -> Maybe BS.ByteString
+formatString str = Just $ "'" <> escapeQuotes "" str <> "'"
   where
     escapeQuotes :: BS.ByteString -> BS.ByteString -> BS.ByteString
     escapeQuotes _ "" = ""
@@ -160,33 +160,33 @@
   toRow _ s = [formatString $ TE.encodeUtf8 $ TL.toStrict s]
 
 instance ToRow backend One Int where
-  toRow _ n = [BS.pack $ show n]
+  toRow _ n = [Just $ BS.pack $ show n]
 
 instance ToRow backend One Int8 where
-  toRow _ n = [BS.pack $ show n]
+  toRow _ n = [Just $ BS.pack $ show n]
 
 instance ToRow backend One Int16 where
-  toRow _ n = [BS.pack $ show n]
+  toRow _ n = [Just $ BS.pack $ show n]
 
 instance ToRow backend One Int32 where
-  toRow _ n = [BS.pack $ show n]
+  toRow _ n = [Just $ BS.pack $ show n]
 
 instance ToRow backend One Int64 where
-  toRow _ n = [BS.pack $ show n]
+  toRow _ n = [Just $ BS.pack $ show n]
 
 instance ToRow backend One Integer where
-  toRow _ n = [BS.pack $ show n]
+  toRow _ n = [Just $ BS.pack $ show n]
 
 instance ToRow backend One Double where
-  toRow _ n = [BS.pack $ show n]
+  toRow _ n = [Just $ BS.pack $ show n]
 
 instance ToRow backend One Float where
-  toRow _ n = [BS.pack $ show n]
+  toRow _ n = [Just $ BS.pack $ show n]
 
 instance (NTimes (Vector n), Backend backend, ToRow backend n a)
   => ToRow backend n (Maybe a) where
   toRow backend = \case
-    Nothing -> ntimes "NULL"
+    Nothing -> ntimes Nothing
     Just x  -> toRow backend x
 
 instance ( NTimes (Vector k), NTimes (Vector l), Backend backend
diff --git a/src/Database/Seakale/Types.hs b/src/Database/Seakale/Types.hs
--- a/src/Database/Seakale/Types.hs
+++ b/src/Database/Seakale/Types.hs
@@ -8,6 +8,7 @@
 import           Control.Monad.Writer
 
 import           Data.List
+import           Data.Maybe
 import qualified Data.ByteString as BS
 import qualified Data.ByteString.Lazy as BSL
 
@@ -111,7 +112,7 @@
     go :: Query n -> QueryData n -> [BS.ByteString]
     go req dat = case (req, dat) of
       (Plain bs req', _) -> bs : go req' dat
-      (Hole req', Cons bs dat') -> bs : go req' dat'
+      (Hole req', Cons mBS dat') -> fromMaybe "NULL" mBS : go req' dat'
       (EmptyQuery, Nil) -> []
 
 formatMany :: RepeatQuery k l i -> QueryData k -> QueryData i -> [QueryData l]
@@ -144,7 +145,7 @@
 deriving instance Show (ColumnType backend) => Show (ColumnInfo backend)
 deriving instance Eq   (ColumnType backend) => Eq   (ColumnInfo backend)
 
-type QueryData n = Vector n BS.ByteString
+type QueryData n = Vector n (Maybe BS.ByteString)
 
 data Vector :: Nat -> * -> * where
   Cons :: a -> Vector n a -> Vector ('S n) a