Progress
SQL-92
Guide and Reference
Date Arithmetic Expressions
Date arithmetic expressions compute the difference between date-time expressions in terms of days or milliseconds. SQL supports these forms of date arithmetic:
This is the syntax for a date_arith_expr:
date_time_expr
Returns a value of type DATE or TIME or TIMESTAMP. A single date-time expression cannot mix data types, however. All elements of the expression must be the same data type.
Date-time expressions can contain date-time literals, but they must be converted to DATE or TIME using the CAST, CONVERT, or TO_DATE functions. See the following examples: CAST Function (SQL-92 Compatible) and CONVERT Function (Progress Extension).
int_expr
Returns an integer value. SQL interprets the integer differently depending on the data type of the date-time expression:
EXAMPLES
The following example manipulates DATE values using date arithmetic. SQL interprets integers as days and returns date differences in units of days:
The following example manipulates TIME values using date arithmetic. SQL interprets integers as milliseconds and returns time differences in milliseconds:
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