This section describes the types of expressions you can write in Maintain:

• Numeric. Use a numeric expression to perform a calculation on numeric constants or variables. For example, you can write an expression to compute the bonus for each employee by multiplying the current salary by the desired percentage as follows:

  COMPUTE Bonus = Curr_Sal * 0.05 ;

  A numeric expression returns a numeric value. For details, see Writing Numeric Expressions.

• Date and time. Use a date and time expression to perform a calculation that involves dates and/or times. For example, you can write an expression to determine when a customer can expect to receive an order by adding the number of days in transit to the date on which you shipped the order as follows:

  COMPUTE Delivery/MDY = ShipDate + 5 ;

  There are two types of date and time expressions:

  • Date expressions, which return a date or an integer that represents the number of days, months, quarters, or years between two dates. For details, see Writing Date Expressions.
  • Date-time expressions. For details, see Writing Date-Time Expressions.
• Alphanumeric. Use an alphanumeric expression to manipulate alphanumeric constants or variables. For example, you can write an expression to extract the first initial from an alphanumeric field as follows:

  COMPUTE First_Init/A1 = MASK (First_Name, '9$$$$$$$$$') ;

  An alphanumeric expression returnsan alphanumeric value. For details, see Writing Alphanumeric Expressions.

• Logical. Use a logical expression to determine whether a particular relationship between two values is true. A logical expression returns TRUE or FALSE. For details see Writing Logical Expressions.
• Conditional. Use a conditional expression to assign a value based on the result of a logical expression. A conditional expression returns a numeric or character value. For details see Writing Conditional Expressions.