如何在字符串中的括号和逗号中获取表达式（regex / PHP）

Question

I think my question is so easy to be solved, but I can't.

I want to take this words inside of my query string:

$string = "INSERT INTO table (a,b) VALUES ('foo', 'bar')";

Expected result:

array one = [a,b]
array two = [foo, bar]

Answer 1

There are many regex strategies you could use for this depending on how flexible you need it to be. Here is one very simple implementation which assumes that you know the string 'VALUES' is in all caps, and there is exactly one space before and after 'VALUES' and the two sets of parenthesis.

$string = "INSERT INTO table (a,b) VALUES ('foo', 'bar')";
$matches = array();

// we escape literal parenthesis in the regex, and also add 
// grouping parenthesis to capture the sections we're interested in

preg_match('/\((.*)\) VALUES \((.*)\)/', $string, $matches);

// make sure the matches you expect to be found are populated
// before referencing their array indices. index 0 is the match of
// our entire regex, indices 1 and 2 are our two sets of parens

if (!empty($matches[1]) && !empty($matches[2]) {
  $column_names = explode(',', $matches[1]); // array of db column names
  $values = explode(',', $matches[2]);  // array of values

  // you still have some clean-up work to do here on the data in those arrays.
  // for instance there may be empty spaces that need to be trimmed from 
  // beginning/ending of some of the strings, and any of the values that were
  // quoted need the quotation marks removed.
}

This is only a starting point, be sure to test it on your data and revise the regex as needed!

I recommend using a regex tester to test your regex string against actual query strings you need it to work on. http://regexpal.com/ (There are many others)