delphi里sql的用法？（高分请教）

Question

query1.SQL.add('select * from stock where c_date=:c_date');
query1.ParambyName('c_date').AsDatetime := DateTimePicker1.Datetime;

Answer 1

query1.SQL.add('select * from stock where c_date='''+Formatdatetime('mm"/"dd"/"yyyy',datetimepicker1.date)+'''');

Answer 2

query1.SQL.add('select * from stock where c_date = ''' + DateTimeToStr(DateTimePicker1.Datetime) + '''');

Answer 3

query1.SQL.add('select * from stock where c_date=:c_date');
query1.ParambyName('c_date').AsDatetime := DateTimePicker1.Datetime;orquery1.SQL.add('select * from stock where c_date='''+Formatdatetime('mm"/"dd"/"yyyy',datetimepicker1.date)+'''');