错误代码：1052-字段列表中的列“ idk”不明确

Question

Hi I trying to create query and add this, query error:

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

full query:

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;

error message:

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

help me to solve this.

this my database https://irhas.online/test/test2.txt please help me.

Answer 1

Your query has a reference to idk (from the @sql_dinamis part) however both your nilai and matakuliah have idk fields in them, so SQL doesn't know which one you want. You need to change the idk in

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

to be either nilai.idk or matakuliah.idk eg

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

This works for me (see DBFiddle )