user: Question: How many of the Royal Waggon Train Unit were Missing while having a Killed of 0 off 0 men and a Wounded of 0 off 0 men?
Columns: ['Unit', 'Complement', 'Killed', 'Wounded', 'Missing']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Head Quarters', '150 off[icers] 1231 men', '0 off 0 men', '2 off 0 men', '0 off 0 men']
SQL:

assistant: SELECT "Missing" FROM "Table" WHERE "Killed" = '0 off 0 men' AND "Wounded" = '0 off 0 men' AND "Unit" = 'Royal Waggon Train';