SQL Server:
select sum(case 字段1 when not null then 1 else 0 end)
+sum(case 字段2 when not null then 1 else 0 end)
+sum(case 字段3 when not null then 1 else 0 end)
from TableName
select sum(case 字段1 when not null then 1 else 0 end)
+sum(case 字段2 when not null then 1 else 0 end)
+sum(case 字段3 when not null then 1 else 0 end)
from TableName
where 字段1 is not null or 字段2 is not null or 字段3 is not null or 字段4 is not null or 字段5 is not null or 字段6 is not null
where (字段1 is not null) and (字段2 is not null) and (字段3 is not null) and (字段4 is not null) and (字段5 is not null) and (字段6 is not null)