mysql - 错误代码:1052-字段列表中的列“id”不明确

嗨，我尝试创建查询并将其添加，查询错误：

JOIN matakuliah ON nilai.idk = matakuliah.idk
WHERE matakuliah.semester = 1

完整查询：

SET @sql_dinamis = ( SELECT GROUP_CONCAT( DISTINCT CONCAT( 'max( IF(idk = ', idk, ',huruf,null) ) AS A', idk ) ) FROM nilai  );

SET @SQL = CONCAT( 'SELECT mahasiswa.nim, mahasiswa.nama, ', @sql_dinamis, '
FROM nilai
JOIN mahasiswa ON nilai.idm = mahasiswa.idm
JOIN matakuliah ON nilai.idk = matakuliah.idk
WHERE matakuliah.semester = 1
GROUP BY nilai.idm' );
PREPARE stmt
FROM
@SQL;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

错误信息：

FROM nilai
JOIN mahasiswa ON nilai.idm = mahasiswa.idm
JOIN matakuliah ON nilai.idk = matakuliah.idk
WHERE matakuliah.semester = 1
GROUP BY nilai.idm' )
> OK
> Time: 0s


PREPARE stmt
FROM
@SQL
> 1052 - Column 'idk' in field list is ambiguous
> Time: 0s

帮我解决这个问题。

这是我的数据库https://irhas.online/test/test2.txt，请帮助我。

最佳答案

您的查询具有对idk的引用（来自@sql_dinamis部分），但是您的nilai和matakuliah都具有idk字段，因此SQL不知道您要哪个。您需要在其中更改idk

SET @sql_dinamis = ( SELECT GROUP_CONCAT( DISTINCT CONCAT( 'max( IF(idk = ', idk, ',huruf,null) ) AS A', idk ) ) FROM nilai  );

例如nilai.idk或matakuliah.idk

SET @sql_dinamis = ( SELECT GROUP_CONCAT( DISTINCT CONCAT( 'max( IF(nilai.idk = ', idk, ',huruf,null) ) AS A', idk ) ) FROM nilai  );

这对我有用（请参见DBFiddle）