Question

Table:articles
id  address     autor   .........
1   name_test1  Paul    ...........
2   name_test2  George  ........

此表包含一些博文。

Table:article-hearts
id  cookie_userid   article_id
1   123             1
2   345             1
3   123             2

当访问者点击＆＃34; Heart It！＆＃34;行动记录在这里。

我想显示每篇博文的心数。在这种语法中，我试图添加心脏计数：

$articles = mysql_query("SELECT * FROM articles ORDER BY date_created, time_created DESC ") or die(mysql_error());

所以它看起来像这样：

 $articles = mysql_query("SELECT a.id, a.address, a.autor, a.date_created, a.time_created, a.title, a.content, a.category, a.reads, ah.cookie_userid, ah.article_id, ah.id, 
COUNT(*) as 'hcount'
FROM
articles AS a
    join 'article_hearts' AS ah where 'ah.article_id' = 'a.id'
    join 'article_hearts' AS ah2 where ah2.article_id=ah.article_id
ORDER BY a.date_created, a.time_created DESC
")or die(mysql_error());

我在第5行得到错误：加入＆＃39; article_hearts＆＃39; AS啊在哪里＆＃39; ah.article_id＆＃39; =＆＃39; a.id＆＃39;

Answer 1

你的语法错了。在连接之后必须是on条件而不是`where considtion。您还必须删除列名称旁边的单引号。

SELECT a.id, a.address, a.autor, a.date_created, a.time_created, a.title, a.content, a.category, a.reads, ah.cookie_userid, ah.article_id, ah.id, 
COUNT(*) as 'hcount'
FROM
articles AS a
    join 'article_hearts' AS ah on ah.article_id= a.id
    join 'article_hearts' AS ah2 on ah2.article_id=ah.article_id
ORDER BY a.date_created, a.time_created DESC

Answer 2

有5个问题：

表格中的引言
两次加入桌子
加入的语法错误
缺少GROUP BY
您在选择
中不需要某些列
$articles = mysql_query( "SELECT a.id, a.address, a.autor, a.date_created, a.time_created, a.title, a.content, a.category, a.reads, COUNT(*) as 'hcount' FROM articles AS a JOIN article_hearts AS ah ON ah.article_id = a.id GROUP BY a.id, a.address, a.autor, a.date_created, a.time_created, a.title, a.content, a.category, a.reads ORDER BY a.date_created, a.time_created DESC") or die(mysql_error());

MYSQL连接和计数语法错误

2 个答案: