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Retrieving Computed Values

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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:

Operator	Explanation
+	addition
-	subtraction
*	multiplication
/	division
||	string concatenation

See the Mimer SQL Reference Manual for information regarding the type and precision of the result of an arithmetic expression.

List room prices with a 12% reduction:

 SELECT  PRICE, PRICE*0.88
 FROM    ROOM_PRICES;

Result:

PRICE
900	792.00
830	730.40
760	668.80
710	624.80
800	704.00
...	...

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  PRICE, PRICE*0.88 AS SPECIAL_RATE
 FROM    ROOM_PRICES;

Result:

PRICE	SPECIAL_RATE
900	792.00
830	730.40
760	668.80
710	624.80
800	704.00
...	...

Constant Values

A column may also be 'computed' as a constant value, which adds an extra column to the result table.

For example:

 SELECT  PRICE, '12% reduction:', PRICE*0.88 AS SPECIAL_RATE
 FROM    ROOM_PRICES;

Result:

PRICE		SPECIAL_RATE
900	12% reduction:	792.00
830	12% reduction:	730.40
760	12% reduction:	668.80
710	12% reduction:	624.80
800	12% reduction:	704.00
...	...	...

You may also retrieve a value computed using the values in two or more columns, providing that the data types are compatible.

Retrieve hotel names prefixed with the word 'HOTEL' and cities:

 SELECT  'HOTEL ' || NAME, CITY
 FROM    HOTEL;

Result:

	CITY
HOTEL LAPONIA	STOCKHOLM
HOTEL SKYLINE	UPPSALA
HOTEL ST. GEORGE	STOCKHOLM
HOTEL Winston	London
HOTEL WINSTON	COPENHAGEN
HOTEL WINSTON	GOTHENBURG

Padding Concatenated Strings

For string concatenation, column values are padded with trailing blanks to the length of the column definition.

For example:

 SELECT  NAME || 'HOTEL', CITY
 FROM    HOTEL;
 

Result:

	CITY
LAPONIA HOTEL	STOCKHOLM
SKYLINE HOTEL	UPPSALA
ST. GEORGE HOTEL	STOCKHOLM
Winston HOTEL	London
WINSTON HOTEL	COPENHAGEN
WINSTON HOTEL	GOTHENBURG

Parentheses

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.

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