如何使用两个不同的别名检索相同的列？

Question

I have one table called 'answers' with four column wherein adding answers with positive and negative rankings and i want to retrieve answer with different aliasing for answer with positive ranks and answer with negative ranks. is there any way to retrieve same column with two different aliases ?

id  answer  rank  question_id

1   Yes      1       1
2   No       2       1
3   True    -2       2
4   False   -1       2

I want to have this answers in the form of comma delimited list I have tried this but no success.

SELECT CASE WHEN a.rank > 0 THEN GROUP_CONCAT(a.answer)  END AS answer,
       CASE WHEN a.rank < 0 THEN GROUP_CONCAT(a.answer)  END AS matrix
FROM answers a.

Answer 1

select group_concat(case when rank > 0 then answer end) as pos_answers,
       group_concat(case when rank < 0 then answer end) as neg_answers
from answers

Answer 2

您可以尝试以下方法：

SELECT GROUP_CONCAT(IF(rank>0,answer,NULL)) as positive_ans, GROUP_CONCAT(IF(rank<0,answer,NULL)) as negative_ans FROM answers