Table: west_end_theatres
Columns: theatre
current_show
classification
capacity
opening_date
closing_date

Question: What is the opening date of the musical at the adelphi theatre?
SQL: SELECT "opening_date" FROM west_end_theatres WHERE "classification" = 'musical' AND "theatre" = 'adelphi theatre'

Question: What opening date has a capacity of 100?
SQL: SELECT "opening_date" FROM west_end_theatres WHERE "capacity" = 100