我有这个 SQL 查询,其中我有一些 case 语句和计数,以便旋转我的“类 x”行,它返回类似这样的内容。
| Nombre Completo | Clase 1 | Clase 2|
--------------------------------------
| Example name | 3 | 5 |
--------------------------------------
我需要的是替换数字,如果数字> 0,则将其替换为是,否则将其替换为否。 我怎样才能做到这一点? Mysql 查询:
SELECT DISTINCT concat_ws(' ',U.firstname, U.lastname) as Nombre_Completo,
COUNT(CASE WHEN b.name="Clase 1" THEN b.name END) Clase1,
COUNT(CASE WHEN b.name="Clase 2" THEN b.name END) Clase2,
COUNT(CASE WHEN b.name="Clase 3" THEN b.name END) Clase3,
COUNT(CASE WHEN b.name="Clase 4" THEN b.name END) Clase4,
COUNT(CASE WHEN b.name="Clase 5" THEN b.name END) Clase5,
COUNT(CASE WHEN b.name="Clase 6" THEN b.name END) Clase6,
COUNT(CASE WHEN b.name="Clase 7" THEN b.name END) Clase7,
COUNT(CASE WHEN b.name="Clase 8" THEN b.name END) Clase8,
COUNT(CASE WHEN b.name="Clase 9" THEN b.name END) Clase9,
COUNT(CASE WHEN b.name="Clase 10" THEN b.name END) Clase10,
COUNT(CASE WHEN b.name="Clase 11" THEN b.name END) Clase11,
COUNT(CASE WHEN b.name="Clase 12" THEN b.name END) Clase12
FROM mdl_logstore_standard_log as L
LEFT JOIN mdl_course as C ON L.courseid = C.id
left JOIN mdl_user as U on L.userid = U.ID
JOIN mdl_bigbluebuttonbn AS b ON L.objectid = b.id
JOIN mdl_role_assignments AS ra ON L.userid = ra.userid
JOIN mdl_role AS r ON r.id = ra.roleid
WHERE (C.shortname LIKE '%CSG012020%') AND (ra.roleid=5) AND (ra.roleid NOT IN (3,4))
GROUP BY Nombre_Completo;
答案 0 :(得分:1)
使用IF()
测试COUNT()
的结果
SELECT DISTINCT concat_ws(' ',U.firstname, U.lastname) as Nombre_Completo,
IF(COUNT(CASE WHEN b.name="Clase 1" THEN b.name END) > 0, 'Yes', 'No') Clase1,
IF(COUNT(CASE WHEN b.name="Clase 2" THEN b.name END) > 0, 'Yes', 'No') Clase2,
IF(COUNT(CASE WHEN b.name="Clase 3" THEN b.name END) > 0, 'Yes', 'No') Clase3,
IF(COUNT(CASE WHEN b.name="Clase 4" THEN b.name END) > 0, 'Yes', 'No') Clase4,
IF(COUNT(CASE WHEN b.name="Clase 5" THEN b.name END) > 0, 'Yes', 'No') Clase5,
IF(COUNT(CASE WHEN b.name="Clase 6" THEN b.name END) > 0, 'Yes', 'No') Clase6,
IF(COUNT(CASE WHEN b.name="Clase 7" THEN b.name END) > 0, 'Yes', 'No') Clase7,
IF(COUNT(CASE WHEN b.name="Clase 8" THEN b.name END) > 0, 'Yes', 'No') Clase8,
IF(COUNT(CASE WHEN b.name="Clase 9" THEN b.name END) > 0, 'Yes', 'No') Clase9,
IF(COUNT(CASE WHEN b.name="Clase 10" THEN b.name END) > 0, 'Yes', 'No') Clase10,
IF(COUNT(CASE WHEN b.name="Clase 11" THEN b.name END) > 0, 'Yes', 'No') Clase11,
IF(COUNT(CASE WHEN b.name="Clase 12" THEN b.name END) > 0, 'Yes', 'No') Clase12
FROM mdl_logstore_standard_log as L
LEFT JOIN mdl_course as C ON L.courseid = C.id
left JOIN mdl_user as U on L.userid = U.ID
JOIN mdl_bigbluebuttonbn AS b ON L.objectid = b.id
JOIN mdl_role_assignments AS ra ON L.userid = ra.userid
JOIN mdl_role AS r ON r.id = ra.roleid
WHERE (C.shortname LIKE '%CSG012020%') AND (ra.roleid=5) AND (ra.roleid NOT IN (3,4))
GROUP BY Nombre_Completo;
答案 1 :(得分:1)
每个:
COUNT(CASE WHEN b.name="Clase X" THEN b.name END)
在你的代码中可以写成:
SUM(b.name='Clase X')
因为 MySql 将 b.name='Clase 1'
之类的布尔表达式计算为 1
(true) 或 0
(false)。
此外,任何整数值都可以解释为 false
,如果它是 0
或 true
,如果它不同于 0
。
所以你可以这样写你的查询:
SELECT concat_ws(' ', U.firstname, U.lastname) Nombre_Completo,
CASE WHEN SUM(b.name='Clase 1') THEN 'yes' ELSE 'no' END Clase1,
CASE WHEN SUM(b.name='Clase 2') THEN 'yes' ELSE 'no' END Clase2,
CASE WHEN SUM(b.name='Clase 3') THEN 'yes' ELSE 'no' END Clase3,
CASE WHEN SUM(b.name='Clase 4') THEN 'yes' ELSE 'no' END Clase4,
CASE WHEN SUM(b.name='Clase 5') THEN 'yes' ELSE 'no' END Clase5,
CASE WHEN SUM(b.name='Clase 6') THEN 'yes' ELSE 'no' END Clase6,
CASE WHEN SUM(b.name='Clase 7') THEN 'yes' ELSE 'no' END Clase7,
CASE WHEN SUM(b.name='Clase 8') THEN 'yes' ELSE 'no' END Clase8,
CASE WHEN SUM(b.name='Clase 9') THEN 'yes' ELSE 'no' END Clase9,
CASE WHEN SUM(b.name='Clase 10') THEN 'yes' ELSE 'no' END Clase10,
CASE WHEN SUM(b.name='Clase 11') THEN 'yes' ELSE 'no' END Clase11,
CASE WHEN SUM(b.name='Clase 12') THEN 'yes' ELSE 'no' END Clase12
FROM mdl_logstore_standard_log as L
LEFT JOIN mdl_course as C ON L.courseid = C.id
left JOIN mdl_user as U on L.userid = U.ID
JOIN mdl_bigbluebuttonbn AS b ON L.objectid = b.id
JOIN mdl_role_assignments AS ra ON L.userid = ra.userid
JOIN mdl_role AS r ON r.id = ra.roleid
WHERE (C.shortname LIKE '%CSG012020%') AND (ra.roleid=5) AND (ra.roleid NOT IN (3,4))
GROUP BY Nombre_Completo;
我删除了 DISTINCT
,因为您 GROUP BY Nombre_Completo
后不需要它。