@@ -241,9 +241,9 @@ our %VALID_DELETE_ARGS

 sub delete {

     my ($self, %args) = @_;

-    # Check arguments

+    # Check argument names

     foreach my $name (keys %args) {

-        croak qq{"$name" is invalid argument}

+        croak qq{Argument "$name" is invalid name}

           unless $VALID_DELETE_ARGS{$name};

     }

@@ -307,9 +307,9 @@ our %VALID_DELETE_AT_ARGS

 sub delete_at {

     my ($self, %args) = @_;

-    # Check arguments

+    # Check argument names

     foreach my $name (keys %args) {

-        croak qq{"$name" is invalid argument}

+        croak qq{Argument "$name" is invalid name}

           unless $VALID_DELETE_AT_ARGS{$name};

     }

@@ -349,9 +349,9 @@ our %VALID_EXECUTE_ARGS = map { $_ => 1 } qw/param filter table/;

 sub execute{

     my ($self, $query, %args)  = @_;

-    # Check arguments

+    # Check argument names

     foreach my $name (keys %args) {

-        croak qq{"$name" is invalid argument}

+        croak qq{Argument "$name" is invalid name}

           unless $VALID_EXECUTE_ARGS{$name};

     }

@@ -369,6 +369,13 @@ sub execute{

     $arg_tables = [$arg_tables]

       unless ref $arg_tables eq 'ARRAY';

     push @$tables, @$arg_tables;

+

+    # Organize tables

+    my %table_set = map {defined $_ ? ($_ => 1) : ()} @$tables;

+    my $main_table = pop @$tables;

+    delete $table_set{$main_table} if $main_table;

+    $tables = [keys %table_set];

+    push @$tables, $main_table if $main_table;

     foreach my $table (@$tables) {

         next unless $table;

@@ -442,9 +449,9 @@ our %VALID_INSERT_ARGS = map { $_ => 1 } qw/table param append

 sub insert {

     my ($self, %args) = @_;

-    # Check arguments

+    # Check argument names

     foreach my $name (keys %args) {

-        croak qq{"$name" is invalid argument}

+        croak qq{Argument "$name" is invalid name}

           unless $VALID_INSERT_ARGS{$name};

     }

@@ -497,9 +504,9 @@ our %VALID_INSERT_AT_ARGS

 sub insert_at {

     my ($self, %args) = @_;

-    # Check arguments

+    # Check argument names

     foreach my $name (keys %args) {

-        croak qq{"$name" is invalid argument}

+        croak qq{Argument "$name" is invalid name}

           unless $VALID_INSERT_AT_ARGS{$name};

     }

@@ -630,9 +637,9 @@ sub _need_tables {

 sub select {

     my ($self, %args) = @_;

-    # Check arguments

+    # Check argument names

     foreach my $name (keys %args) {

-        croak qq{"$name" is invalid argument}

+        croak qq{Argument "$name" is invalid name}

           unless $VALID_SELECT_ARGS{$name};

     }

@@ -651,23 +658,26 @@ sub select {

     croak qq{"join" must be array reference}

       unless ref $join eq 'ARRAY';

+    # Join tables

     my @join_tables;

     unshift @join_tables, $tables->[-1];

-    # Relation table(DEPRECATED!);

-    $self->_add_relation_table($args{relation}, $tables);

+    # Add relation tables(DEPRECATED!);

+    $self->_add_relation_table($tables, $args{relation});

     # SQL stack

     my @sql;

-    

     push @sql, 'select';

+    # Selection

     if ($selection) {

         push @sql, $selection;

         push @join_tables, @{$self->_tables($selection)};

     }

+    

+    # Column names and table name

     else {

-        # Column clause

+        # Column names

         if (@$columns) {

             foreach my $column (@$columns) {

                 push @join_tables, @{$self->_tables($column)};

@@ -691,9 +701,7 @@ sub select {

     if (ref $where eq 'HASH') {

         my $clause = ['and'];

         push @$clause, "{= $_}" for keys %$where;

-        $w = $self->where;

-        $w->clause($clause);

-        $w->param($where);

+        $w = $self->where(clause => $clause, param => $where);

     }

     elsif (ref $where eq 'DBIx::Custom::Where') {

         $w = $where;

@@ -706,7 +714,7 @@ sub select {

     # String where

     my $swhere = "$w";

-    # Table name in Where

+    # Add table names in where clause to join talbes.

     unshift @join_tables, @{$self->_tables($swhere)};

     # Join

@@ -744,7 +752,7 @@ sub select {

         }

     }

-    # Add where

+    # Add where clause

     push @sql, $swhere;

     # Relation(DEPRECATED!);

@@ -777,9 +785,9 @@ our %VALID_SELECT_AT_ARGS

 sub select_at {

     my ($self, %args) = @_;

-    # Check arguments

+    # Check argument names

     foreach my $name (keys %args) {

-        croak qq{"$name" is invalid argument}

+        croak qq{Argument "$name" is invalid name}

           unless $VALID_SELECT_AT_ARGS{$name};

     }

@@ -921,9 +929,9 @@ our %VALID_UPDATE_ARGS

 sub update {

     my ($self, %args) = @_;

-    # Check arguments

+    # Check argument names

     foreach my $name (keys %args) {

-        croak qq{"$name" is invalid argument}

+        croak qq{Argument "$name" is invalid name}

           unless $VALID_UPDATE_ARGS{$name};

     }

@@ -1020,9 +1028,9 @@ our %VALID_UPDATE_AT_ARGS

 sub update_at {

     my ($self, %args) = @_;

-    # Check arguments

+    # Check argument names

     foreach my $name (keys %args) {

-        croak qq{"$name" is invalid argument}

+        croak qq{Argument "$name" is invalid name}

           unless $VALID_UPDATE_AT_ARGS{$name};

     }

@@ -1078,7 +1086,8 @@ sub where {

     return DBIx::Custom::Where->new(

         query_builder => $self->query_builder,

-        safety_column_name => $self->safety_column_name

+        safety_column_name => $self->safety_column_name,

+        @_

     );

 }

@@ -1234,7 +1243,7 @@ sub _push_relation {

 # DEPRECATED!

 sub _add_relation_table {

-    my ($self, $relation, $tables) = @_;

+    my ($self, $tables, $relation) = @_;

     if (keys %{$relation || {}}) {

         foreach my $rcolumn (keys %$relation) {

@@ -1887,7 +1896,10 @@ the key and value is delete from C<param>.

 =head2 C<(experimental) where>

-    my $where = $dbi->where;

+    my $where = $dbi->where(

+        clause => ['and', '{= title}', '{= author}'],

+        param => {title => 'Perl', author => 'Ken'}

+    );

 Create a new L<DBIx::Custom::Where> object.

@@ -236,7 +236,7 @@ $rows = $dbi->select(table => 'table1')->fetch_hash_all;

 is_deeply($rows, [{key1 => 1, key2 => 2}], 'insert append');

 eval{$dbi->insert(table => 'table1', noexist => 1)};

-like($@, qr/noexist/, "invalid argument");

+like($@, qr/noexist/, "invalid");

 eval{$dbi->insert(table => 'table', param => {';' => 1})};

 like($@, qr/safety/);

@@ -285,7 +285,7 @@ is_deeply($rows, [{key1 => 1, key2 => 22, key3 => 3, key4 => 4, key5 => 5},

 $result = $dbi->update(table => 'table1', param => {key2 => 11}, where => {key1 => 1}, append => '   ');

 eval{$dbi->update(table => 'table1', noexist => 1)};

-like($@, qr/noexist/, "invalid argument");

+like($@, qr/noexist/, "invalid");

 eval{$dbi->update(table => 'table1')};

 like($@, qr/where/, "not contain where");

@@ -359,7 +359,7 @@ $rows = $dbi->select(table => 'table1')->fetch_hash_all;

 is_deeply($rows, [{key1 => 3, key2 => 4}], "delete multi key");

 eval{$dbi->delete(table => 'table1', noexist => 1)};

-like($@, qr/noexist/, "invalid argument");

+like($@, qr/noexist/, "invalid");

 $dbi = DBIx::Custom->connect($NEW_ARGS->{0});

 $dbi->execute($CREATE_TABLE->{0});

@@ -437,7 +437,7 @@ $rows = $dbi->select(

 is_deeply($rows, [{table1_key1 => 1, table2_key1 => 1, key2 => 2, key3 => 5}], "relation : no exists where");

 eval{$dbi->select(table => 'table1', noexist => 1)};

-like($@, qr/noexist/, "invalid argument");

+like($@, qr/noexist/, "invalid");

 test 'fetch filter';

@@ -514,7 +514,7 @@ $dbi->execute($CREATE_TABLE->{0});

 }

 eval{$dbi->execute('select * from table1', no_exists => 1)};

-like($@, qr/\Q"no_exists" is invalid argument/, "invald SQL");

+like($@, qr/invalid/, "invald SQL");

 $query = $dbi->create_query('select * from table1 where {= key1}');

 $dbi->dbh->disconnect;