From: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Date: Sat, 26 Jan 2013 19:55:38 +0000 (+0000)
Subject: Add support for NULLS FIRST/LAST in ORDER BY
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=dbsrgits%2FSQL-Abstract.git;a=commitdiff_plain;h=36e3ea6ca294fa0c1a32cefa39ec23146498faf0

Add support for NULLS FIRST/LAST in ORDER BY
---

diff --git a/Changes b/Changes
index 674d881..59487f2 100644
--- a/Changes
+++ b/Changes
@@ -7,6 +7,7 @@ Revision history for SQL::Abstract
     - Fix incorrect reporting of mismatch-members in SQLA::Test
     - Migrate the -ident operator from DBIC into SQLA
     - Migrate the -value operator from DBIC into SQLA
+    - Add support for NULLS FIRST/LAST in ORDER BY
 
 revision 1.72  2010-12-21
 ----------------------------
diff --git a/lib/SQL/Abstract/Converter.pm b/lib/SQL/Abstract/Converter.pm
index 8779cce..1f5414b 100644
--- a/lib/SQL/Abstract/Converter.pm
+++ b/lib/SQL/Abstract/Converter.pm
@@ -200,7 +200,7 @@ sub _select_to_dq {
 
   my $ordered_dq = do {
     if ($order) {
-      $self->_order_by_to_dq($order, undef, $source_dq);
+      $self->_order_by_to_dq($order, undef, undef, $source_dq);
     } else {
       $source_dq
     }
@@ -517,13 +517,14 @@ sub _where_hashpair_to_dq {
 }
 
 sub _order_by_to_dq {
-  my ($self, $arg, $dir, $from) = @_;
+  my ($self, $arg, $dir, $nulls, $from) = @_;
 
   return unless $arg;
 
   my $dq = Order(
     undef,
     (defined($dir) ? (!!($dir =~ /desc/i)) : undef),
+    (defined($nulls) ? ($nulls =~ /first/i ? 1 : -1) : undef),
     ($from ? ($from) : undef),
   );
 
@@ -536,7 +537,7 @@ sub _order_by_to_dq {
     my ($outer, $inner);
     foreach my $member (@$arg) {
       local $Order_Inner;
-      my $next = $self->_order_by_to_dq($member, $dir, $from);
+      my $next = $self->_order_by_to_dq($member, $dir, $nulls, $from);
       $outer ||= $next;
       $inner->{from} = $next if $inner;
       $inner = $Order_Inner || $next;
@@ -564,15 +565,27 @@ sub _order_by_to_dq {
       $dq->{by} = $self->_literal_to_dq($$arg);
     }
   } elsif (ref($arg) eq 'HASH') {
-    my ($key, $val, @rest) = %$arg;
+    return () unless %$arg;
+
+    my ($direction, $val);
+    foreach my $key (keys %$arg) {
+      if ( $key =~ /^-(desc|asc)/i ) {
+        die "hash passed to _order_by_to_dq must have exactly one of -desc or -asc"
+            if defined $direction;
+        $direction = $1;
+        $val = $arg->{$key};
+      } elsif ($key =~ /^-nulls$/i)  {
+        $nulls = $arg->{$key};
+        die "invalid value for -nulls" unless $nulls =~ /^(?:first|last)$/;
+      } else {
+        die "invalid key in hash passed to _order_by_to_dq";
+      }
+    }
 
-    return unless $key;
+    die "hash passed to _order_by_to_dq must have exactly one of -desc or -asc"
+        unless defined $direction;
 
-    if (@rest or not $key =~ /^-(desc|asc)/i) {
-      die "hash passed to _order_by must have exactly one key (-desc or -asc)";
-    }
-    my $dir = uc $1;
-    return $self->_order_by_to_dq($val, $dir, $from);
+    return $self->_order_by_to_dq($val, $direction, $nulls, $from);
   } else {
     die "Can't handle $arg in _order_by_to_dq";
   }
diff --git a/t/06order_by.t b/t/06order_by.t
index 25a4f32..2b3b13f 100644
--- a/t/06order_by.t
+++ b/t/06order_by.t
@@ -104,10 +104,25 @@ my @cases =
     expects_quoted => ' ORDER BY colA, colB LIKE ? DESC, colC LIKE ?',
     bind => [qw/test tost/],
    },
+   {
+    given => [ { -asc => 'colA', -nulls => 'first' }, { -desc => 'colB', -nulls => 'last' } ],
+    expects => ' ORDER BY colA NULLS FIRST, colB DESC NULLS LAST',
+    expects_quoted => ' ORDER BY `colA` NULLS FIRST, `colB` DESC NULLS LAST',
+   },
+   {
+    given => [ { -asc => 'colA', -nulls => 'first' }, { -desc => 'colB', -nulls => 'last' } ],
+    expects => ' ORDER BY colA NULLS FIRST, colB DESC NULLS LAST',
+    expects_quoted => ' ORDER BY `colA` NULLS FIRST, `colB` DESC NULLS LAST',
+   },
+   {
+    given => { -asc => [qw/colA colB/], -nulls => 'first' } ,
+    expects => ' ORDER BY colA NULLS FIRST, colB NULLS FIRST',
+    expects_quoted => ' ORDER BY `colA` NULLS FIRST, `colB` NULLS FIRST',
+   },
   );
 
 
-plan tests => (scalar(@cases) * 2) + 2;
+plan tests => (scalar(@cases) * 2) + 4;
 
 my $sql  = SQL::Abstract->new;
 my $sqlq = SQL::Abstract->new({quote_char => '`'});
@@ -134,12 +149,24 @@ for my $case( @cases) {
 
 throws_ok (
   sub { $sql->_order_by({-desc => 'colA', -asc => 'colB' }) },
-  qr/hash passed .+ must have exactly one key/,
+  qr/hash passed .+ must have exactly one of/,
   'Undeterministic order exception',
 );
 
 throws_ok (
   sub { $sql->_order_by({-desc => [ qw/colA colB/ ], -asc => [ qw/colC colD/ ] }) },
-  qr/hash passed .+ must have exactly one key/,
+  qr/hash passed .+ must have exactly one of/,
   'Undeterministic order exception',
 );
+
+throws_ok(
+  sub { $sql->_order_by({-wibble => "fleem" }) },
+  qr/invalid key in hash/,
+  'Invalid order exception',
+);
+
+throws_ok(
+  sub { $sql->_order_by({-nulls => "fleem" }) },
+  qr/invalid value for -nulls/,
+  'Invalid nulls exception',
+);