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select item, type, description, data1 from [Table] where data1 Is not null
Union
select item, type, description, data2 from [Table] where data2 Is not null
Union
select item, type, description, data3 from [Table] where data3 Is not null
ИЛИ
select * from (
select item, type, description, data1 as data from [Table]
Union
select item, type, description, data2 as data from [Table]
Union
select item, type, description, data3 as data from [Table] )
where data is not null