X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FSQLAHacks.pm;h=5c374b0766570fdd5fd24690444be3746f4bf998;hb=c2ecf953198fc6c43edae1b39de4cc86debcb11b;hp=81661fbaff0aaa254833d16756b9a555603e5650;hpb=8637bb249bdda94dbbe47ad898cde0b7e89bad20;p=dbsrgits%2FDBIx-Class-Historic.git

diff --git a/lib/DBIx/Class/SQLAHacks.pm b/lib/DBIx/Class/SQLAHacks.pm
index 81661fb..5c374b0 100644
--- a/lib/DBIx/Class/SQLAHacks.pm
+++ b/lib/DBIx/Class/SQLAHacks.pm
@@ -47,31 +47,62 @@ sub new {
 }
 
 
-# Slow but ANSI standard Limit/Offset support. DB2 uses this
+# ANSI standard Limit/Offset implementation. DB2 and MSSQL use this
 sub _RowNumberOver {
   my ($self, $sql, $order, $rows, $offset ) = @_;
 
-  $offset += 1;
-  my $last = $rows + $offset - 1;
-  my ( $order_by ) = $self->_order_by( $order );
+  # get the select to make the final amount of columns equal the original one
+  my ($select) = $sql =~ /^ \s* SELECT \s+ (.+?) \s+ FROM/ix
+    or croak "Unrecognizable SELECT: $sql";
 
-  $sql = <<"SQL";
-SELECT * FROM
-(
-   SELECT Q1.*, ROW_NUMBER() OVER( ) AS ROW_NUM FROM (
-      $sql
-      $order_by
-   ) Q1
-) Q2
-WHERE ROW_NUM BETWEEN $offset AND $last
+  # get the order_by only (or make up an order if none exists)
+  my $order_by = $self->_order_by(
+    (delete $order->{order_by}) || $self->_rno_default_order
+  );
 
-SQL
+  # whatever is left of the order_by
+  my $group_having = $self->_order_by($order);
+
+  my $qalias = $self->_quote ($self->{_dbic_rs_attrs}{alias});
+
+  $sql = sprintf (<<EOS, $offset + 1, $offset + $rows, );
+
+SELECT $select FROM (
+  SELECT $qalias.*, ROW_NUMBER() OVER($order_by ) AS rno__row__index FROM (
+    ${sql}${group_having}
+  ) $qalias
+) $qalias WHERE rno__row__index BETWEEN %d AND %d
+
+EOS
 
+  $sql =~ s/\s*\n\s*/ /g;   # easier to read in the debugger
   return $sql;
 }
 
-# Crappy Top based Limit/Offset support. MSSQL uses this currently,
-# but may have to switch to RowNumberOver one day
+# some databases are happy with OVER (), some need OVER (ORDER BY (SELECT (1)) )
+sub _rno_default_order {
+  return undef;
+}
+
+# Informix specific limit, almost like LIMIT/OFFSET
+sub _SkipFirst {
+  my ($self, $sql, $order, $rows, $offset) = @_;
+
+  $sql =~ s/^ \s* SELECT \s+ //ix
+    or croak "Unrecognizable SELECT: $sql";
+
+  return sprintf ('SELECT %s%s%s%s',
+    $offset
+      ? sprintf ('SKIP %d ', $offset)
+      : ''
+    ,
+    sprintf ('FIRST %d ', $rows),
+    $sql,
+    $self->_order_by ($order),
+  );
+}
+
+# Crappy Top based Limit/Offset support. Legacy from MSSQL.
 sub _Top {
   my ( $self, $sql, $order, $rows, $offset ) = @_;
 
@@ -376,7 +407,7 @@ sub _recurse_fields {
       $self->_sqlcase($func),
       $self->_recurse_fields($args),
       $as
-        ? sprintf (' %s %s', $self->_sqlcase('as'), $as)
+        ? sprintf (' %s %s', $self->_sqlcase('as'), $self->_quote ($as) )
         : ''
     );