Retrieving Computed Values
You can retrieve computed values by using arithmetic and string operators in the SELECT clause of the statement.
The following computational operators may be used:
addition subtraction multiplication division string concatenation
See the Mimer SQL Reference Manual, Chapter 5, SQL Syntax Elements, for information regarding the type and precision of the result of an arithmetic expression.
Show the exchange rate for the US Dollar if there was a 10% change:SELECT exchange_rate, exchange_rate * 0.90 FROM currencies WHERE code = 'USD';
Labels and Computed Values
The computed column is unnamed by default in the result table. A label may be used to provide a name.
For example:SELECT exchange_rate, exchange_rate * 0.90 AS new_exchange_rate FROM currencies WHERE code = 'USD';
A column may also be computed as a constant value, which adds an extra column to the result table.
For example:SELECT exchange_rate, '10% reduction:', exchange_rate * 0.90 AS new_exchange_rate FROM currencies WHERE code = 'USD';
You may also retrieve a value computed using the values in two or more columns, providing that the data types are compatible.
Retrieve the currencies prefixed with the word "Currency:":SELECT 'Currency: ' || currency FROM currencies WHERE code LIKE 'A%';
Padding Concatenated Strings
For string concatenation, column values are padded with trailing blanks to the length of the column definition.
For example:SELECT currency || 'Currency' FROM currencies WHERE code LIKE 'A%';
When retrieving computed values, parentheses can be used to force the operation priority.
Without parentheses, the normal precedence rules for arithmetic apply, i.e. multiplication and division are performed before addition and subtraction, and operators with the same precedence are evaluated from left to right.
Upright Database Technology AB
Voice: +46 18 780 92 00
Fax: +46 18 780 92 40