How do you check sql query is correct or not in php?

From MySQL 5.6.3 on you can use EXPLAIN for most queries

I made this and it works lovely:

function checkMySqlSyntax[$mysqli, $query] {
   if [ trim[$query] ] {
      // Replace characters within string literals that may *** up the process
      $query = replaceCharacterWithinQuotes[$query, '#', '%'] ;
      $query = replaceCharacterWithinQuotes[$query, ';', ':'] ;
      // Prepare the query to make a valid EXPLAIN query
      // Remove comments # comment ; or  # comment newline
      // Remove SET @var=val;
      // Remove empty statements
      // Remove last ;
      // Put EXPLAIN in front of every MySQL statement [separated by ;] 
      $query = "EXPLAIN " .
               preg_replace[Array["/#[^\n\r;]*[[\n\r;]|$]/",
                              "/[Ss][Ee][Tt]\s+\@[A-Za-z0-9_]+\s*:?=\s*[^;]+[;|$]/",
                              "/;\s*;/",
                              "/;\s*$/",
                              "/;/"],
                        Array["","", ";","", "; EXPLAIN "], $query] ;

      foreach[explode[';', $query] as $q] {
         $result = $mysqli->query[$q] ;
         $err = !$result ? $mysqli->error : false ;
         if [ ! is_object[$result] && ! $err ] $err = "Unknown SQL error";
         if [ $err] return $err ;
      }
      return false ;
  }
}

function replaceCharacterWithinQuotes[$str, $char, $repl] {
    if [ strpos[ $str, $char ] === false ] return $str ;

    $placeholder = chr[7] ;
    $inSingleQuote = false ;
    $inDoubleQuotes = false ;
    $inBackQuotes = false ;
    for [ $p = 0 ; $p < strlen[$str] ; $p++ ] {
        switch [ $str[$p] ] {
            case "'": if [ ! $inDoubleQuotes && ! $inBackquotes ] $inSingleQuote = ! $inSingleQuote ; break ;
            case '"': if [ ! $inSingleQuote && ! $inBackquotes ] $inDoubleQuotes = ! $inDoubleQuotes ; break ;
            case '`': if [ ! $inSingleQuote && ! $inDoubleQuotes ] $inBackquotes  = ! $inBackquotes ; break ;
            case '\\': $p++ ; break ;
            case $char: if [ $inSingleQuote || $inDoubleQuotes || $inBackQuotes] $str[$p] = $placeholder ; break ;
        }
    }
    return str_replace[$placeholder, $repl, $str] ;
 }

It wil return False if de query is OK [multiple ; separated statements allowed], or an error message stating the error if there is a syntax or other MySQL other [like non-existent table or column].

PHP Fiddle

KNOWN BUGS:

• MySQL errors with linenumbers: the linenumbers mostly will not match.
• Does not work for MySQL statements other than SELECT, UPDATE, REPLACE, INSERT, DELETE