Yesterday’s date in cast context

TypeCHAR(9), or depends on explicit CAST

'YESTERDAY' is not a variable, but a string literal. It is, however, special in the sense that when you CAST() it to a date/time type, you will get the date of the day before. See also Section 12.20, “'TODAY'”.

Examples

  |select 'Yesterday' from rdb$database
  |-- returns 'Yesterday'
  | 
  |select cast('Yesterday as date) from rdb$database
  |-- returns e.g. 2011-10-02
  | 
  |select cast('YESTERDAY' as timestamp) from rdb$database
  |-- returns e.g. 2011-10-02 00:00:00.0000