錯誤代碼：1052-字段列表中的列“ idk”不明確

Question

嗨，我嘗試創建查詢並將其添加，查詢錯誤：

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

完整查詢：

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;

錯誤信息：

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

幫我解決這個問題。

這是我的數據庫https://irhas.online/test/test2.txt，請幫助我。

Answer 1

您的查詢具有對idk的引用（來自@sql_dinamis部分），但是您的nilai和matakuliah都具有idk字段，因此SQL不知道您要哪個。 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  );

例如為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  );

這對我有用 （請參閱DBFiddle ）