Mysql 对查询w的更正

执行查询时：

SELECT DISTINCT (u.name),u.class,
(SELECT ( markscored) FROM marklist WHERE subject LIKE 'biology' AND u.id=m.id) AS biology,
(SELECT ( markscored) FROM marklist WHERE subject LIKE 'chemistry' AND u.id=m.id) AS chemistry,
(SELECT ( markscored) FROM marklist WHERE subject LIKE ' physics' AND u.id=m.id) AS physics,
(SELECT SUM( markscored) FROM marklist WHERE u.id=m.id) AS TOTAL,
(SELECT SUM(outof) FROM marklist WHERE u.id=m.id) AS OUTOF,


((SELECT SUM( markscored) FROM marklist WHERE u.id=m.id)/(SELECT SUM(outof) FROM marklist WHERE u.id=m.id)*100) as percentage
FROM  u, marklist m
WHERE u.id=m.userid 

我得到一个错误，如下所示：

错误1242（21000）：子查询返回超过1行

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我怎样才能解决这个问题呢？

以下内容可能对您有所帮助。 除数不能为0，因此如果将其更改为NULL，请使用NULL

    SELECT  u.name,u.class,
       SUM( markscored) AS TOTAL,
       SUM(outof) AS OUTOF
       SUM(CASE WHEN subject LIKE 'biology' THEN markscored ELSE 0 END) AS biology,
       SUM(CASE WHEN subject LIKE 'chemistry' THEN markscored ELSE 0 END) AS chemistry,
       SUM(CASE WHEN subject LIKE 'physics' THEN markscored ELSE 0 END) AS physics,
       SUM( markscored)/NULLIF(SUM(outof),0) as percentage

    FROM  u, marklist m
    WHERE u.id=m.userid
    GROUP BY u.name,u.class

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子查询返回多个行，并且该子查询需要返回单个标量值才能使其有意义。请稍等片刻，将您的问题格式化，正如你期望SO社区花时间回答它一样。请更正我的查询，以获得准确的输出：+------------------+--------+--------+--------+--------+--------+--------+--------+--------+----名称|类|生物|化学|物理|总数|超出|百分比|+--------+---------+--------+---------+---------+---------+----+---------+---------+----+----阿伦| 5 | 45 | 42 |40 | 150 | 127 | 84.6 |请包括样本数据和预期输出。在没有解释的情况下，直接在so上转储一个查询是不太好的。您需要什么解释请回答…………注意，DISTINCT不是一个函数选择u.name、u.class、SUM（当主题为“生物学”时为CASE，然后markscored ELSE 0 END）作为生物学，SUM（当主题为“化学”时为CASE，然后markscored ELSE 0 END）作为化学，SUM（当科目如“物理”时，则markscored ELSE 0结束）作为物理，总和（markscored）作为总计，总和（outof）作为outof FROM u，marklist m，其中u.id=m.userid按u.name分组，u.class；