请我试图在选择计数(*)上获取关联列值。这是我的代码。
$res = mysql_query("select count(*) as total from table where reg = '12' GROUP BY YEAR DESC LIMIT 7");
while($r4 = mysql_fetch_assoc($res)){
$totalscore = $r4['AVERAGE'];
$len = $r4['total'];
}
$len
返回我的期望值,而列AVERAGE是未定义的,即$totalscore = $r4['AVERAGE'];
AVERAGE是我的数据库上的列。这是否意味着我不能获取关联列值,如果我的sql语句是计数(*)?什么好主意吗?
您没有在查询中选择average
列您可以选择更多列,如下所示:
SELECT
COUNT(*) as total,
`AVERAGE`
FROM table
WHERE reg = '12'
GROUP BY YEAR DESC
LIMIT 7