select room.roomtype,inhotel.innum,workname from room -> join inhotel on inhotel.roomnum=room.roomnum -> join(select workname from worker)workname on inhotel.worknum=worker.worknum; ERROR 1054 (42S22): Unknown column 'worker.worknum' in 'on clause'

根据你提供的 SQL 语句，错误提示是无法识别 "worker.worknum" 这个列名，这是因为你在子查询中创建了一个名为 "workname" 的子查询表，但是你在主查询中的 JOIN 子句中使用了错误的表别名。

应该将子查询表的别名 "workname" 修改为 "worker"，如下所示：

SELECT room.roomtype, inhotel.innum, workname 
FROM room 
JOIN inhotel ON inhotel.roomnum = room.roomnum 
JOIN (SELECT workname, worknum FROM worker) AS worker ON inhotel.worknum = worker.worknum;

这样应该可以解决问题。

相关问题

select room.roomtype,inhotel.innum,worker.worker.workname from room -> join inhotel on inhotel.roomnum=room.roomnum -> join(select workname,worknum from worker)workname on inhotel.worknum=workname.worknum -> join worker on workname.workname=worker.worknamr; ERROR 1054 (42S22): Unknown column 'worker.worker.workname' in 'field list'

根据你提供的 SQL 语句，出现了两个错误：

1. 在第一行中，应该将 "worker.worker.workname" 修改为 "worker.workname"。
2. 在第三行中，应该将 "workname.workname" 修改为 "workname"。

修改后的 SQL 语句如下：

SELECT room.roomtype, inhotel.innum, worker.workname 
FROM room 
JOIN inhotel ON inhotel.roomnum = room.roomnum 
JOIN (SELECT workname, worknum FROM worker) AS workname ON inhotel.worknum = workname.worknum 
JOIN worker ON workname.workname = worker.workname;

这样应该可以解决问题。

select room.roomtype,inhotel.innum,worker.workname from room -> join inhotel on inhotel.roomnum=room.roomnum -> join(select workname from worker)worker on inhotel.worknum=worker.worknum; ERROR 1054 (42S22): Unknown column 'worker.worknum' in 'on clause'

根据你提供的 SQL 语句，错误提示是无法识别 "worker.worknum" 这个列名，这是因为你在子查询中创建了一个名为 "worker" 的子查询表，但是你在主查询中的 JOIN 子句中使用了错误的表别名。

应该将子查询表的别名 "worker" 修改为 "w" 或其他别名，如下所示：

SELECT room.roomtype, inhotel.innum, worker.workname 
FROM room 
JOIN inhotel ON inhotel.roomnum = room.roomnum 
JOIN (SELECT workname, worknum FROM worker) AS w ON inhotel.worknum = w.worknum
JOIN worker ON w.workname = worker.workname;

这样应该可以解决问题。