sql查询一个字段多列值合并为一列sql 多列合并成一列查询多列合并一列，group by合并一列查询，多列数据

1、针对1对多，查询合并多列的情况场景解决方案：

SELECT
  t.news_id,
  t.sentiment_label AS '情感', ( 
CASE WHEN    t.sentiment_label=1
then '负面'
WHEN    t.sentiment_label=2
then '中性'
ELSE   '正面'
END
) as  '情感描述'
FROM
  tbm_popular_feelings t
WHERE
  t.sentiment_label IS NOT NULL
AND t.create_time BETWEEN '2021-01-10 09:55:00'
AND '2021-01-14 09:55:00'
ORDER BY   t.id  desc;

运行结果：

2、合并结果，多列为一列：

运行的SQL语句：

关键字：

    GROUP_CONCAT(t.sentiment_label) AS '情感'

SELECT
    t.news_id,
      GROUP_CONCAT(t.sentiment_label) AS '情感'
  FROM
    tbm_popular_feelings t
  WHERE
    t.sentiment_label IS NOT NULL
  AND t.create_time BETWEEN '2021-01-10 09:55:00'
  AND '2021-01-14 09:55:00'
 GROUP BY
 t.news_id;

运行结果：

3、进行编码枚举描述说明，进一步优化SQL显示结果更为友好：

SELECT
  t.news_id,
  GROUP_CONCAT(t.sentiment_label) AS '情感',
  GROUP_CONCAT(
    CASE
    WHEN t.sentiment_label = 1 THEN
      '负面'
    WHEN t.sentiment_label = 2 THEN
      '中性'
    ELSE
      '正面'
    END
  ) AS '情感描述'
FROM
  tbm_popular_feelings t
WHERE
  t.sentiment_label IS NOT NULL
AND t.create_time BETWEEN '2021-01-10 09:55:00'
AND '2021-01-14 09:55:00'
GROUP BY
  t.news_id;

运行结果如下：

看起来更为友好！