From f4e0c12cba5e35cc6ec8fab9c2e714a3fad66d54 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Crist=C3=B3v=C3=A3o?= <jmacristovao@gmail.com>
Date: Thu, 12 Feb 2015 11:31:56 +0000
Subject: [PATCH 1/2] IS/IS NOT null, true, false

---
 src/PgQuery.hs | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/PgQuery.hs b/src/PgQuery.hs
index bcec5c114..38a230156 100644
--- a/src/PgQuery.hs
+++ b/src/PgQuery.hs
@@ -139,13 +139,18 @@ update t cols vals = B.Stmt
   empty True
 
 wherePred :: Net.QueryItem -> PStmt
-wherePred (col, predicate) = B.Stmt
-  (" " <> cs (pgFmtIdent $ cs col) <> " " <> op <> " " <> cs sqlValue)
-  empty True
+wherePred (col, predicate) =
+  B.Stmt (" " <> cs (pgFmtIdent $ cs col) <> " " <> op <> " " <>
+      if opCode `elem` ["is","isnot"] then whiteList value
+                                 else cs sqlValue)
+      empty True
 
   where
     opCode:rest = T.split (=='.') $ cs $ fromMaybe "." predicate
     value = T.intercalate "." rest
+    whiteList val = fromMaybe (cs (pgFmtLit val) <> "::unknown ")
+                              (L.find ((==) . T.toLower $ val)
+                                      ["null","true","false"])
 
     star c = if c == '*' then '%' else c
     unknownLiteral = (<> "::unknown ") . pgFmtLit
@@ -166,6 +171,8 @@ wherePred (col, predicate) = B.Stmt
          "like"-> "like"
          "ilike"-> "ilike"
          "in"  -> "in"
+         "is"    -> "is"
+         "isnot" -> "is not"
          _     -> "="
 
 orderParse :: Net.Query -> [OrderTerm]

From f7ff08edf763ca665efdbf6c2acb5bc0a2ed6c5c Mon Sep 17 00:00:00 2001
From: Joe Nelson <cred+github@begriffs.com>
Date: Sun, 15 Mar 2015 15:13:15 -0700
Subject: [PATCH 2/2] Test is.null matcher

---
 CHANGELOG.md              | 3 ++-
 test/Feature/QuerySpec.hs | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 22062fcae..9f92b46d0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## Unreleased
 ### Added
-- Option to specify nulls first or last, eg /people?order=age.desc.nullsfirst
+- Option to specify nulls first or last, eg `/people?order=age.desc.nullsfirst`
+- Filter nulls, `?col=is.null` and `?col=isnot.null`
 
 ## [0.2.7.0] - 2015-03-03
 ### Added
diff --git a/test/Feature/QuerySpec.hs b/test/Feature/QuerySpec.hs
index 2029be092..2bfcbaa78 100644
--- a/test/Feature/QuerySpec.hs
+++ b/test/Feature/QuerySpec.hs
@@ -34,6 +34,10 @@ spec =
         , matchHeaders = ["Content-Range" <:> "0-2/3"]
         }
 
+    it "matches nulls" $
+      get "/no_pk?a=is.null" `shouldRespondWith`
+        [json| [{"a": null, "b": null}] |]
+
     it "matches with like" $ do
       get "/simple_pk?k=like.*yx" `shouldRespondWith`
         "[{\"k\":\"xyyx\",\"extra\":\"u\"}]"