简单的查询生成器，假设PDO
## for simple tokenisation, the terms are separated by space here. ## ###############################################################$string = "( C AND kernel ) OR ( C++ AND UML )";function emit_term( $tag ) {$res = " EXISTS ( SELECt * FROM skill_usage su JOIN skill_names sn ON sn.skill_id = su.skill_id WHERe su.Job_id = j.job_id AND sn.skillname = :" . $tag . ")n";return $res;}$fixed_part ="SELECt job_id, job_name FROM jobs j WHERe 1=1 AND n" ;# $tokens = explode( ' ' , $string ); #splits on any single space$tokens = preg_split( '/[s]+/' , $string ); # accepts multiple whitespace# print_r ( $tokens );$query = $fixed_part;$args = array();$num = 1;foreach ( $tokens as $tok ) { switch ($tok) { case '': # skip empty tokens case ';': # No, you should not! case '"': case "'": case ';': break; case '(': $query .= '('; break; case ')': $query .= ')'; break; case '&': case 'AND': $query .= ' AND '; break; case '|': case 'OR': $query .= ' OR '; break; case '!': case 'NOT': $query .= ' NOT '; break; default: $tag = '_q' . $num ; $query .= emit_term ( $tag ); $args[$tag] = $tok; $num += 1; break; } }$query .= ";nn";echo "Query + parameters (for PDO):n" ;echo $query;print_r ( $args) ;输出：
SELECt job_id, job_name FROM jobs j WHERe 1=1 AND ( EXISTS ( SELECt * FROM skill_usage su JOIN skill_names sn ON sn.skill_id = su.skill_id WHERe su.Job_id = j.job_id AND sn.skillname = :_q1) AND EXISTS ( SELECt * FROM skill_usage su JOIN skill_names sn ON sn.skill_id = su.skill_id WHERe su.Job_id = j.job_id AND sn.skillname = :_q2)) OR ( EXISTS ( SELECt * FROM skill_usage su JOIN skill_names sn ON sn.skill_id = su.skill_id WHERe su.Job_id = j.job_id AND sn.skillname = :_q3) AND EXISTS ( SELECt * FROM skill_usage su JOIN skill_names sn ON sn.skill_id = su.skill_id WHERe su.Job_id = j.job_id AND sn.skillname = :_q4));Array( [_q1] => C [_q2] => kernel [_q3] => C++ [_q4] => UML)
