add the --delete helper option to ysql

The `--delete` helper option allows us to generate `DELETE FROM` queries,
optionally with a `WHERE` clause (the `--where` option).

Refs #136

bin/ysql

@@ -48,6 +48,7 @@ __END__
 
     ysql <db_name> --select <table>
     ysql <db_name> --insert <table>
+    ysql <db_name> --delete <table>
 
     ysql <db_name> --save <query_name> <query>
     ysql <db_name> --edit <query_name>
@@ -128,6 +129,10 @@ And for simple inserts, we can use the C<--insert> helper:
 
     $ ysql db_name --insert person < input.yml
 
+There is a C<--delete> helper as well, which accepts the C<--where> option:
+
+    $ ysql db_name --delete person --where 'dept = "Wildlife"'
+
 =head1 ARGUMENTS
 
 =head2 db_name
@@ -154,6 +159,11 @@ Generate an C<INSERT INTO table ( fields ) VALUES ( values )> query for the
 given C<table>. For each document read on STDIN, the correct fields and values
 will be used.
 
+=head2 --delete <table>
+
+Generate a C<DELETE FROM table> query for the given C<table>. Also accepts
+the C<--where> option.
+
 =head2 --where <clause>
 
 Add a C<WHERE> clause to a C<--select> query.

lib/ETL/Yertl/Command/ysql.pm

@@ -35,6 +35,7 @@ sub main {
         'edit|e=s',
         'select=s',
         'insert=s',
+        'delete=s',
         'where=s',
         'order|order-by|sort=s',
     );
@@ -203,6 +204,9 @@ sub main {
         if ( $opt{select} ) {
             $query = $sql->select( $opt{select}, '*', $opt{where}, $opt{order} );
         }
+        elsif ( $opt{delete} ) {
+            $query = $sql->delete( $opt{delete}, $opt{where} );
+        }
         else {
             $query = shift @args;
 

t/bin/ysql.t

@@ -629,6 +629,40 @@ subtest 'query' => sub {
                 );
         };
 
+        subtest '--delete' => sub {
+            my ( $home, $dbh ) = $setup->();
+            local $ENV{HOME} = "$home";
+
+            my ( $stdout, $stderr, $exit ) = capture {
+                ysql->main( 'testdb', '--delete', 'person' );
+            };
+            is $exit, 0;
+            ok !$stderr, 'nothing on stderr' or diag $stderr;
+            ok !$stdout, 'nothing on stdout' or diag $stdout;
+
+            cmp_deeply
+                $dbh->selectall_arrayref( 'SELECT id,name,email FROM person' ),
+                [];
+
+            subtest '--where' => sub {
+                my ( $home, $dbh ) = $setup->();
+                local $ENV{HOME} = "$home";
+
+                my ( $stdout, $stderr, $exit ) = capture {
+                    ysql->main( 'testdb', '--delete', 'person', '--where', 'id >= 2' );
+                };
+                is $exit, 0;
+                ok !$stderr, 'nothing on stderr' or diag $stderr;
+                ok !$stdout, 'nothing on stdout' or diag $stdout;
+
+                cmp_deeply
+                    $dbh->selectall_arrayref( 'SELECT id,name,email FROM person' ),
+                    bag(
+                        [ 1, 'Hazel Murphy', '[email protected]' ],
+                    );
+            };
+
+        };
     };
 
     subtest 'saved queries' => sub {