Question

如何将这个SELECT转换为带有字符串的输出（在此示例下方）？

nose_1

|id|class|about_education|
| 1|    1|            a01|
| 2|    0|            a02|

coins_2

|id|class|about_education|
| 1|    1|            a01|
| 2|    0|            a02|

money_3

|id|class|about_education|
| 1|    1|            a01|
| 2|    1|            a10|


SELECT 
     COUNT(CASE WHEN about_education = 'a01' and class = 1 then 1 else 0 end) a01,
     COUNT(CASE WHEN about_education = 'a02' and class = 1 then 1 else 0 end) a02, 
     COUNT(CASE WHEN about_education = 'a03' and class = 1 then 1 else 0 end) a03, 
     COUNT(CASE WHEN about_education = 'a04' and class = 1 then 1 else 0 end) a04, 
     COUNT(CASE WHEN about_education = 'a05' and class = 1 then 1 else 0 end) a05, 
     COUNT(CASE WHEN about_education = 'a06' and class = 1 then 1 else 0 end) a06, 
     COUNT(CASE WHEN about_education = 'a07' and class = 1 then 1 else 0 end) a07, 
     COUNT(CASE WHEN about_education = 'a08' and class = 1 then 1 else 0 end) a08, 
     COUNT(CASE WHEN about_education = 'a09' and class = 1 then 1 else 0 end) a09,
     COUNT(CASE WHEN about_education = 'a10' and class = 1 then 1 else 0 end) a10
FROM 
(
  SELECT id,class,about_education from nose_1
  UNION ALL
  SELECT id,class,about_education FROM coins_2
  UNION ALL
  SELECT id,class,about_education FROM money_3
) t

输出：

$check_a01 = 3;
$check_a02 = 0;
$check_a03 = 0;
$check_a04 = 0;
$check_a05 = 0;
$check_a06 = 0;
$check_a07 = 0;
$check_a08 = 0;
$check_a09 = 0;
$check_a10 = 1;

Lorem ipsum dolor坐下，私服精英人士，sed do eiusmod tempor incididunt ut Labore et dolore magna aliqua。尽量不要抽烟，不要因抽烟而锻炼，而要从中抽签。

Answer 1

您可以在THEN之后的所有1放在引号中，而在ELSE之后的所有0放在引号中。

then '1' else '0' end

Answer 2

我不理解您的要求，希望下面的代码对您有所帮助

SELECT 
    CONCAT('$check_',
            about_education,
            ' = ',
            SUM(CASE
                WHEN
                    SUBSTRING(t.about_education,
                        2,
                        LENGTH(t.about_education)) = a.id
                        AND class = 1
                THEN
                    1
                ELSE 0
            END),
            ';') AS output
FROM
    (SELECT 
        class, about_education
    FROM
        nose_1 UNION ALL SELECT 
        class, about_education
    FROM
        coins_2 UNION ALL SELECT 
        class, about_education
    FROM
        money_3) t
        JOIN
    (SELECT 1 AS Id UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9 UNION SELECT 10) a ON SUBSTRING(t.about_education,
        2,
        LENGTH(t.about_education)) = a.id
GROUP BY t.about_education;

如何将“ this” SELECT转换为多个字符串

2 个答案: