query2sql.php

<?php
function valueToSQL($value) {
    switch (gettype($value)) {
        case 'string':
            return "'" . $value . "'";
        case 'boolean':
            return $value ? '1' : '0';
        case 'integer':
            if (is_finite($value)) return $value;
        case 'double':
            if (is_finite($value)) return $value;
    }
}

function rulesMap($rule)
{
    if(isset($rule['rules'])){
        return "(" . basicRulesetToSQL($rule) . ")";
    }
    
    $column = "";
    $column = $rule['field'];

    switch ($rule['operator']){
        case "is null":
        case "is not null":
            $operator = $rule['operator'];
            $value = "";
            break;
        case "in":
        case "not in":
            $operator = $rule['operator'];
            if (is_array($rule['value']) && sizeof($rule['value']))
                $value = array_map('valueToSQL', $rule['value']);
                $value = array_filter($value);
                $value = join(", ", $temp);
                $value .= ")";
                $value = "(" . $value;
            break;
        default:
            $operator = $rule['operator'];
            $value = valueToSQL($rule['value']);
            break;
    }
    if(isset($column) && isset($value) && isset($operator)){
        return "(" . trim($column . " " . $operator . " " . $value) . ")";
    }
}

function basicRulesetToSQL($ruleset) {
    $temp = array_map('rulesMap', $ruleset['rules']);
    $temp = array_filter($temp);
    $temp = join(" " . $ruleset['condition'] . " ", $temp);
    return $temp;
}

$data = json_decode('{
  "condition": "and",
  "rules": [
    {
      "condition": "and",
      "rules": [
        {
          "field": "Born in",
          "operator": ">",
          "value": "1945"
        },
        {
          "field": "Submission to the party",
          "operator": "<",
          "value": "1984"
        }
      ]
    },
    {
      "field": "nickname",
      "operator": "=",
      "value": "6079 Smith W"
    },
    {
      "field": "Name",
      "operator": "=",
      "value": "Winston Smith"
    }
  ]
}', TRUE);


echo basicRulesetToSQL($data);
?>