public function getTrimExpression($str, $pos = self::TRIM_UNSPECIFIED, $char = false)
{
if (!$char) {
switch ($pos) {
case self::TRIM_LEADING:
$trimFn = 'LTRIM';
break;
case self::TRIM_TRAILING:
$trimFn = 'RTRIM';
break;
default:
return 'LTRIM(RTRIM(' . $str . '))';
}
return $trimFn . '(' . $str . ')';
}
/** Original query used to get those expressions
declare @c varchar(100) = 'xxxBarxxx', @trim_char char(1) = 'x';
declare @pat varchar(10) = '%[^' + @trim_char + ']%';
select @c as string
, @trim_char as trim_char
, stuff(@c, 1, patindex(@pat, @c) - 1, null) as trim_leading
, reverse(stuff(reverse(@c), 1, patindex(@pat, reverse(@c)) - 1, null)) as trim_trailing
, reverse(stuff(reverse(stuff(@c, 1, patindex(@pat, @c) - 1, null)), 1, patindex(@pat, reverse(stuff(@c, 1, patindex(@pat, @c) - 1, null))) - 1, null)) as trim_both;
*/
$pattern = "'%[^' + {$char} + ']%'";
if ($pos == self::TRIM_LEADING) {
return 'stuff(' . $str . ', 1, patindex(' . $pattern . ', ' . $str . ') - 1, null)';
}
if ($pos == self::TRIM_TRAILING) {
return 'reverse(stuff(reverse(' . $str . '), 1, patindex(' . $pattern . ', reverse(' . $str . ')) - 1, null))';
}
return 'reverse(stuff(reverse(stuff(' . $str . ', 1, patindex(' . $pattern . ', ' . $str . ') - 1, null)), 1, patindex(' . $pattern . ', reverse(stuff(' . $str . ', 1, patindex(' . $pattern . ', ' . $str . ') - 1, null))) - 1, null))';
}