substraction field type time
<p>I'm a beginner php-mysql programmer,, and i have some problem,, 1 of them is ....</p>

<p>i have a table "gangguan83" with field</p>

<pre><code>urut_gangguan int(15) -&gt; primary key.
lv int(10),
trip datetime,
masuk datetime,
current int(10),
ens int(10),
....
</code></pre>

<p>how can i query if my statement like this :</p>

<pre><code>ens = (lv * 1,73 * 0,9 * current * (masuk-trip))
</code></pre>

<p>please help me.
Thanks very much before.</p>
