Question

请在底部查看最后的编辑

我在phpMyAdmin中使用MySQL进行以下查询：

(SELECT 
  id, 
  name, 
  rank1, 
  rank2 
FROM rank_list 
LEFT JOIN names ON names.id = rank_list.name_id 
WHERE type = "typeA" 
ORDER BY rank1
LIMIT 50) 

UNION ALL

(SELECT 
  id, 
  name, 
  rank1, 
  rank2 
FROM rank_list 
LEFT JOIN names ON names.id = rank_list.name_id 
WHERE type = "typeB" 
ORDER BY rank2 
LIMIT 50)

它的作用是获得rank1的{{1}}的前50名排名，并将其与typeA的{{1}}的前50名排名合并。
我需要在每个分项rank2周围加上括号，因为我将 typeB和SELECT都声明。
两个人都很好。

问题

将LIMIT应用于两个查询时出现以下错误：

ORDER BY

我真的不在这里...可能引起这一问题的原因是，如果UNION（与A non-numeric value encountered相同，并且在{{1} rank1。

还是这里还有其他东西？

编辑：

当我不对其应用-1时，它确实可以工作

编辑2

我发现执行以下操作（使用括号）时，也会遇到相同的错误：

type = "typeB"

Answer 1

尝试使用强制转换为数据类型

  (SELECT 
    id, 
    name, 
    cast(rank1 AS SIGNED ), 
    cast(rank2  AS SIGNED )
  FROM rank_list 
  LEFT JOIN names ON names.id = rank_list.name_id 
  WHERE type = "typeA" 
  ORDER BY rank1
  LIMIT 50) 

  UNION ALL

  (SELECT 
    id, 
    name, 
    cast(rank1 AS SIGNED ), 
    cast(rank2  AS SIGNED )
  FROM rank_list 
  LEFT JOIN names ON names.id = rank_list.name_id 
  WHERE type = "typeB" 
  ORDER BY rank2 
  LIMIT 50)

Answer 2

我无法复制您的问题

drop table if exists rank_list,names;
create table rank_list
(id int,name_id int,rank1 int,rank2 int,type varchar(10));
create table names
(id int, name varchar(3));

insert into rank_list values
(1,1,1,1,'typea'),(2,2,3,1,'typea'),
(2,2,1,1,'typeb');

insert into names values
(1,'aaa'),(2,'bbb');

(SELECT 
  rank_list.id, 
  name, 
  rank1, 
  rank2 
FROM rank_list 
LEFT JOIN names ON names.id = rank_list.name_id 
WHERE type = "typeA" 
ORDER BY rank1 desc
LIMIT 50) 

UNION ALL

(SELECT 
  rank_list.id, 
  name, 
  rank1, 
  rank2 
FROM rank_list 
LEFT JOIN names ON names.id = rank_list.name_id 
WHERE type = "typeB" 
ORDER BY rank2 desc
LIMIT 50);

+------+------+-------+-------+
| id   | name | rank1 | rank2 |
+------+------+-------+-------+
|    2 | bbb  |     3 |     1 |
|    1 | aaa  |     1 |     1 |
|    2 | bbb  |     1 |     1 |
+------+------+-------+-------+
3 rows in set (0.00 sec)

请注意，我具有完全合格的ID，如果您的型号不同，那么如果您没有更多的输入，任何答案或评论都将是猜测。

在SELECT语句中使用带有LIMIT的括号时出现错误“遇到非数值”

2 个答案: