如何将这两个查询合并为一个？

【问题标题】：How can I merge these two queries into one?如何将这两个查询合并为一个？
【发布时间】：2011-06-28 00:00:07
【问题描述】：

$a = mysql_query("SELECT COUNT(*) as `count_1` FROM `table_1` WHERE `this_1` = '1'");
$b = mysql_fetch_assoc($a);

$c = mysql_query("SELECT COUNT(*) as `count_2` FROM `table_1` WHERE `this_2` = '1'");
$d = mysql_fetch_assoc($c);

【问题讨论】：

标签： php mysql merge

【解决方案1】：

使用 UNION ALL 使其成为单个查询：

SELECT COUNT(*) as count_1 FROM table_1 WHERE this_1 = '1' 联合所有 SELECT COUNT(*) as count_2 FROM table_1 WHERE this_2 = '1'

这样会导致

$a = mysql_query("...the complete query from above...");

【讨论】：

【解决方案2】：

您可以在 COUNT() 中使用条件来计算出现次数。这样，您将获得包含多列的单行：

SELECT COUNT(this_1 = '1' OR NULL) AS count_1, COUNT(this_2 = '1' OR NULL) AS count_2

【讨论】：