Question

我有一个mysql表

id      cid    c_name       keywords
 1       28    Stutgart    BW,Mercedes,Porsche,Auto,Germany
 2       34    Roma        Sezar,A.S. Roma
 3       28    München     BMW,Oktober Fest,Auto,Germany

我需要一个查询来显示来自cid = 28的关键字，但我想只看一次关键字，如（BW，Mercedes，Porsche，Auto，Bmw，Oktober Fest，Germany）我不想列出2次关键字，如何解决这个问题？

我尝试过不同但却无法得到我想要的东西

Answer 1

在将所有内容添加到DISTINCT之前拆分它。当然，最好是规范化您的数据（列中的值不超过1）

SELECT
  GROUP_CONCAT( DISTINCT SUBSTRING_INDEX(SUBSTRING_INDEX(keywords, ',', n.digit+1), ',', -1)) keyword
FROM
  t
  INNER JOIN
  (SELECT 0 digit UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3  UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6) n
  ON LENGTH(REPLACE(keywords, ',' , '')) <= LENGTH(keywords)-n.digit
WHERE cid=28

See it working

Answer 2

如果要获取动态输出，则可以使用以下查询在单个记录中获取以逗号分隔的不同值。

Note: here doesn't matter how many values are in comma delimited row & it's fetched distinct record from a number of rows based on your condition

$tag_list = DB::select('SELECT
                          TRIM(TRAILING "," FROM REPLACE(GROUP_CONCAT(DISTINCT keywords, ","),",,",",")) tag_list
                          FROM
                          test
                          WHERE id = 28');

$unique_tags = implode(',', array_unique(explode(",",$result[0]->search_tags)));

mysql选择不同的逗号分隔值

2 个答案: