This SQL Query will filter out all of the invalid system enclosure asset tags using NOT NULL, Not Like (<>) and NOT IN SQL commands.
SQL Query:
Select
SD.Name0 'Machine Name',
SD.User_Name0 'User Name',
SE.SmBiosAssetTag0 'Asset Tag'
From v_R_System SD
Join v_GS_System_Enclosure SE On SD.ResourceID = SE.ResourceID
Where SD.Client0 = '1'
And SE.SmBiosAssetTag0 Is Not Null
And SE.SmBiosAssetTag0 <> '%ÿ%'
And SE.SmBiosAssetTag0 not in ('Not Available', 'No Asset Information','')
87cd8ea7-68b5-49fb-8878-fd931813d75d|0|.0
SQL