Zend\Db\Sql Allow MySQL to use limit when only offset was provided

[ralphschindler]

This is a fix for #5642
And would supersede PR #5643

[samsonasik]

@ralphschindler it still doesn't work if I do :

$table = 'users';
$sampleTable = new TableGateway($table, $adapter, null,new HydratingResultSet());
$select = new Select($table);
$select->offset(10);
echo $select->getSqlString(new \Zend\Db\Adapter\Platform\Mysql);

I tried to test it in Zend\Db\Sql\SelectTest.php with

$select46 = new Select;
        $select46->from('foo')->offset("10");
        $sqlPrep46 = 'SELECT "foo".* FROM "foo" LIMIT ? OFFSET ?';
        $sqlStr46 = 'SELECT "foo".* FROM "foo" LIMIT \'18446744073709551615\' OFFSET \'10\'';
        $params46 = array('limit' => "18446744073709551615", 'offset' => 10);
        $internalTests46 = array(
            'processSelect' => array(array(array('"foo".*')), '"foo"'),
            'processLimit'  => array('?'),
            'processOffset' => array('?')
        );

and I got :

--- Expected
+++ Actual
@@ @@
-'SELECT "foo".* FROM "foo" LIMIT '18446744073709551615' OFFSET '10''
+'SELECT "foo".* FROM "foo" OFFSET '10''

[ralphschindler]

That is correct. You need to use the Zend\Db\Sql\Sql object to get a platform specific SQL string, see the original issue. He is using the SQL object to prepare a statement customized for the mysql platform. So your example would more likely be:

use Zend\Db\Sql;
$sql = new Sql\Sql;
$select = $sql->select($table);
$select->offset(10);
echo $sql->getSqlStringForSqlObject($select);

[samsonasik]

so, using getSqlString is wrong way ?

[samsonasik]

the getSqlString passed the platform too (Zend\Db\Adapter\Platform\PlatformInterface) :

echo $select->getSqlString(new \Zend\Db\Adapter\Platform\Mysql);

[ralphschindler]

echo $select->getSqlString(new \Zend\Db\Adapter\Platform\Mysql);

Will produce a SQL string with the proper quoting/adapter abstraction, but not with the proper SQL abstraction applied. For SQL language abstraction, then Zend\Db\Sql\Sql should be used.

[samsonasik]

Ok, but I tried to use big offset to test yours in ZendTest/Db/Sql/Platform/Mysql/SelectDecoratorTest.php with :

        $select2 = new Select;
        $select2->from('foo')->limit(5)->offset(10000000000000000000);
        $expectedPrepareSql2 = 'SELECT `foo`.* FROM `foo` LIMIT ? OFFSET ?';
        $expectedParams2 = array('offset' => 10000000000000000000, 'limit' => 5);
        $expectedSql2 = 'SELECT `foo`.* FROM `foo` LIMIT 5 OFFSET 10000000000000000000';

--- Expected
+++ Actual
@@ @@
-'SELECT `foo`.* FROM `foo` LIMIT 5 OFFSET 10000000000000000000'
+'SELECT `foo`.* FROM `foo` LIMIT 5 OFFSET 1.0E+19'

so I think $this->limit and $this->offset should not be cast to (int).

[ralphschindler]

Ok, we can remove the casting.

[ralphschindler]

Ok, I've fixed it and added tests. The problem with your above example is that that number you're passing into offset() is actually not an integer, it will be used as a float as it is outside the maximum allowable integer space in PHP. You'll need to pass it as a string, as I've noted in my tests.

[samsonasik]

@ralphschindler thank you ;)

[samsonasik]

@ralphschindler I created PR #5941 to remove cast to (int) in Zend\Db\Sql\Select.php too for offset and limit.