CaseBuilder.php

<?php

class CaseBuilder {
    private $conditions = [];

    public function plain($plain)
    {
        if(is_string($plain)) $this->conditions[] = $plain;
        if(is_array($plain)) $this->conditions = array_merge($this->conditions, $plain);
        return $this;
    }
    public function case($case = null) {
        $array = ["CASE"];
        if ($case) $array[] = "`$case`";
        return $this->plain($array);
    }

    public function when($column, $operator = null, $value = null)
    {
        $array = ["WHEN `$column`"];
        if ($operator) {
            $array[] = $operator;
            $array[] = "`$value`";
        }
        return $this->plain($array);
    }

    public function then($value)
    {
        return $this->plain("THEN `$value`");
    }

    public function else($value)
    {
        return $this->plain("ELSE `$value`");
    }

    public function end()
    {
        return $this->plain("END");
    }

    public function as($as)
    {
        return $this->plain("AS `$as`");
    }

    public function toRaw()
    {
        return implode(' ', $this->conditions);
    }
}