多表查询同一字段

[dllj]

我有5张表，表名分别为a,b,c,d,e，该5表中都有id,form_name,form_number,time，zt四个字段，我想通过一个查询,使5张表中zt=1的记录全部显示出来，请教如何实现？？？
$sql=mysq_query("select ????? where zt=1");
echo "<table>";
while ($tab=mysql_fetch_array($sql)) {
echo "<tr><td>";
echo "<a href=./echo.php?t=$tab[form_number] & id=$tab[id]>$tab[form_name]</a>";
echo "</td><td>";
echo "$tab[time]";
echo "</td></tr>";
}
echo "</table>";

[hzg7361]

SELECT id,form_name,form_number,time，zt FROM a WHERE zt=1
union all
SELECT id,form_name,form_number,time，zt FROM b WHERE zt=1
*
*
*
*

[leohuang]

select id,form_name,form_number,time,zt from a,b,c,d,e where a.zt=1 and b.zt=1 and c.zt=1 and d.zt=1 and e.zt=1

[lvlfforever]

$tab = array('a','b','c','d','e');
$c = count($tab);
$sql = "";
for($i=0;$i<$c;$i++)
{


$sql .= "select {$tab[$i]}.id as fid,{$tab[$i]}.form_name as fname,{$tab[$i]}.form_number as fnum,{$tab[$i]}.time as ftime from
{$tab[$i]} where {$tab[$i]}.zt=1 ";
if($i != $c -1)
$sql .=" union all ";


}
echo $sql;

[zeroleonhart]

select id,form_name,form_number,time，zt from a,b,c,d,e where zt=1

[dlrmq]

$t=array('a','b','c','d','e');
$s=count($t);
$sql="";
for ($i=0;$i<=$s;$i++) {
$sql.="SELECT id,form_name,form_number,time,zt FROM $t[$i] WHERE zt=1 union all ";
}

$sql=substr("$sql",0,-10);
$ttt=mysql_query($sql);