/**
* Generates the LIMIT part of a SQL query
*
* @param int $limit the limit clause
* @param Query $query The query that is being compiled
* @return string
*/
protected function _buildLimitPart(int $limit, Query $query) : string
{
if ($limit === null || $query->clause('offset') === null) {
return '';
}
return sprintf(' FETCH FIRST %d ROWS ONLY', $limit);
}
/**
* Helper function used to build the string representation of a SELECT clause,
* it constructs the field list taking care of aliasing and
* converting expression objects to string. This function also constructs the
* DISTINCT clause for the query.
*
* @param array $parts list of fields to be transformed to string
* @param Query $query The query that is being compiled
* @param ValueBinder $generator the placeholder generator to be used in expressions
* @return string
*/
protected function _buildSelectPart(array $parts, Query $query, ValueBinder $generator) : string
{
$select = 'SELECT %s%s%s';
if ($this->_orderedUnion && $query->clause('union')) {
$select = '(SELECT %s%s%s';
}
$distinct = $query->clause('distinct');
$modifiers = $query->clause('modifier') ?: null;
$normalized = [];
$parts = $this->_stringifyExpressions($parts, $generator);
foreach ($parts as $k => $p) {
if (!is_numeric($k)) {
$p = $p . ' AS ' . "`{$k}`";
}
$normalized[] = $p;
}
if ($distinct === true) {
$distinct = 'DISTINCT ';
}
if (is_array($distinct)) {
$distinct = $this->_stringifyExpressions($distinct, $generator);
$distinct = sprintf('DISTINCT ON (%s) ', implode(', ', $distinct));
}
if ($modifiers !== null) {
$modifiers = $this->_stringifyExpressions($modifiers, $generator);
$modifiers = implode(' ', $modifiers) . ' ';
}
return sprintf($select, $distinct, $modifiers, implode(', ', $normalized));
}
/**
* Prepares a sql statement to be executed
*
* @param \CoreTyson\Database\Query $query The query to convert into a statement.
* @return \CoreTyson\Database\Statement\AbstractStatement
*/
public function prepare($query) : AbstractStatement
{
if (!$this->isConnected()) {
$this->connect();
}
$isObject = $query instanceof Query;
$statement = $this->_PdoConnection->prepare($isObject ? $query->sql() : $query);
return new PdoStatement($statement, $this);
}