MySQL 8.0

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select version();


version()


8.0.27


create table my_table (
id int,
fileid1 int,
fileid2 int,
fileid3 int,
LanguageID1 varchar(10),
LanguageID2 varchar(10),
LanguageID3 varchar(10) );


insert into my_table values
(1,123,256,null,'a12','a23',null),
(2,124,null,null,'a12',null,null),
(3,124,null,null,'a12',null,'a16');	
select id, Fileid, LanguageID
from (
        select id,fileid1 as Fileid,LanguageID1 as LanguageID 
        from  my_table 
      union all 
        select id,fileid2 as Fileid ,LanguageID2 as LanguageID
        from  my_table 
      union all 
       select id,fileid3 as Fileid ,LanguageID3 as LanguageID
       from  my_table 
       ) as t1
where concat_ws('',Fileid,LanguageID) !=''       
       


id
Fileid
LanguageID


1
123
a12

2
124
a12

3
124
a12

1
256
a23

3
null
a16