如何修复子查询返回的一行以上错误


How do i fix subquery returns more than 1 row error

我正在执行此查询

$sql=mysql_query("SELECT c.*,
  (SELECT Count(b.text) From tbl_people_comment  Where b.idsms=c.id AND b.visible=1) AS ccomment
FROM tbl_peoplesms AS c
INNER JOIN tbl_people_comment AS b ON b.idsms= c.id
WHERE c.visible=1
GROUP BY c.id");

我正试图让它在php 中返回这样的东西

 [
      {
      "id":"20", 
      "name":"test",
      "text":"test",
      "visible":"1",
      "ccomment":"5"
      },
      {
      "id":"19",
      "name":"test",
      "text":"test",
      "visible":"1"
      "ccomment":"7" 
      }
    ]

我用这个代码显示

while($row=mysql_fetch_assoc($sql)) 
$output[]=$row; 
print(json_encode($output, JSON_UNESCAPED_UNICODE));

然而,我得到了一个错误,子查询返回超过1行。

这是tbl_peoplesmstbl_peoplesms

和tbl_people_commenttbl_people_comment

不使用内联子查询,只需在tbl_peoplesms上留下join tbl_pepeople_comment,并将b.visible=1条件移动到join子句中:

SELECT c.name, count(b.text) as ccomment
FROM tbl_peoplesms AS c
LEFT JOIN tbl_people_comment AS b ON b.idsms= c.id and b.visible=1
GROUP BY c.name

如果您想在选择列表中包括tbl_people_comment表中的更多字段,那么也可以将它们添加到groupby子句中。