将多个mysql查询合并为一个

Question

我正在学习结合多个查询的Mysql命令和方法，因此为了实现该目标，现在我需要结合以下查询：

    list($TotalVisitsToday) = $db->sql_fetchrow($db->sql_query("SELECT  COUNT(DISTINCT ip_address) FROM table_iptracking WHERE `date_time` between '$yesterday' and '$today' "));
    list($TotalVisitsYesterday) = $db->sql_fetchrow($db->sql_query("SELECT  COUNT(DISTINCT ip_address) FROM table_iptracking WHERE `date_time` between '$yesterday_1' and '$yesterday'  "));

    list($TotalPVisitsToday) = $db->sql_fetchrow($db->sql_query("SELECT count(ipid) FROM table_iptracking WHERE `date_time` between '$yesterday' and '$today'"));
    list($TotalPVisitsYesterday) = $db->sql_fetchrow($db->sql_query("SELECT count(ipid) FROM table_iptracking WHERE `date_time` between '$yesterday_1' and '$yesterday'"));

    list($TotalCrawlers) = $db->sql_fetchrow($db->sql_query("SELECT count(ipid) FROM table_iptracking WHERE  hostname LIKE '%crawl%' "));

我不知道如何混合以上内容！

Answer 1

您可以将SQL语句形成一个UNION，类似...

SELECT COUNT(DISTINCT ip_address)
    FROM table_iptracking
    WHERE `date_time` between '$yesterday' and '$today'
UNION
SELECT COUNT(DISTINCT ip_address)
    FROM table_iptracking
    WHERE `date_time` between '$yesterday_1' and '$yesterday'
UNION
SELECT count(ipid)
    FROM table_iptracking
    WHERE `date_time` between '$yesterday' and '$today'
UNION
SELECT count(ipid)
    FROM table_iptracking
    WHERE `date_time` between '$yesterday_1' and '$yesterday'
UNION
SELECT count(ipid)
    FROM table_iptracking
    WHERE hostname LIKE '%crawl%'

我不能说我会推荐这个。 从长远来看，不同行表示不同事物的结果集可能会带来麻烦。

Answer 2

我不确定您的最终目标，但是如果您只想在一个查询中使用它，就可以这样做：

SELECT
(SELECT COUNT(DISTINCT ip_address) FROM table_iptracking WHERE 'date_time' between '$yesterday' and '$today') COUNT1,
(SELECT COUNT(DISTINCT ip_address) FROM table_iptracking WHERE 'date_time' between '$yesterday_1' and     '$yesterday') COUNT2,
(SELECT COUNT(ipid) FROM table_iptracking WHERE 'date_time' between '$yesterday' and '$today') COUNT3,
(SELECT COUNT(ipid) FROM table_iptracking WHERE 'date_time' between '$yesterday_1' and '$yesterday') COUNT4,
(SELECT COUNT(ipid) FROM table_iptracking WHERE  hostname LIKE '%crawl%') COUNT5

（您可以在MySQL中省略FROM运算符）