我有一个表,其中2列表示用户ID。ID的顺序可以是任意一种(取决于进程的发起者),我需要为两个用户组合检索行(不管是哪种方式)。我的问题是,你们认为最快/最低的开销是什么?SELECT * FROM table WHERE (user1 = 1 AND user2 = 2) OR (user1 = 2 AND user2 = 1) SELECT * FROM table WHERE user1 IN (1, 2) AND user2
$year;
$sql = mysql_query("SELECT start_time, server FROM classesWHERE date = '$date'");
echo "show all the times1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19
我有一张有几行的表格。每条记录都有一个唯一的ID,一个与另一个实体相关的ID,最后一个与最后一个实体相关的注释。SELECT entity_id, COUNT(*) AS amount FROM comments GROUP BY entity_id ORDER BY amount DESC这个查询做的正是我想要的,但是我想回显那个伪列'amount‘的值。可以这样做吗,或者我应该使用另一种方法,比如<e