AVG function
Derby Reference Manual
114
· If the first argument is positive and the second argument is zero, the result is the
double value closest to pi/2.
· If the first argument is negative and the second argument is zero, the result is the
double value closest to -pi/2.
The data type of the returned value is a DOUBLE PRECISION number.
Syntax
ATAN2 ( y, x )
AVG function
AVG is an aggregate function that evaluates the average of an expression over a set of
rows (see
). AVG is allowed only on expressions that evaluate
to numeric data types.
Syntax
AVG ( [ DISTINCT | ALL ] Expression )
The DISTINCT qualifier eliminates duplicates. The ALL qualifier retains duplicates. ALL
is the default value if neither ALL nor DISTINCT is specified. For example, if a column
contains the values 1.0, 1.0, 1.0, 1.0, and 2.0, AVG(col) returns a smaller value than
AVG(DISTINCT col).
Only one DISTINCT aggregate expression per
the following query is not valid:
SELECT AVG (DISTINCT flying_time), SUM (DISTINCT miles)
FROM Flights
The expression can contain multiple column references or expressions, but it cannot
contain another aggregate or subquery. It must evaluate to an SQL-92 numeric data type.
You can therefore call methods that evaluate to SQL-92 data types. If an expression
evaluates to NULL, the aggregate skips that value.
The resulting data type is the same as the expression on which it operates (it will never
overflow). The following query, for example, returns the INTEGER 1, which might not be
what you would expect:
SELECT AVG(c1)
FROM (VALUES (1), (1), (1), (1), (2)) AS myTable (c1)
CAST the expression to another data type if you want more precision:
SELECT AVG(CAST (c1 AS DOUBLE PRECISION))
FROM (VALUES (1), (1), (1), (1), (2)) AS myTable (c1)
BIGINT function
The BIGINT function returns a 64-bit integer representation of a number or character
string in the form of an integer constant.
Syntax
BIGINT (CharacterExpression | NumericExpression )
CharacterExpression
An expression that returns a character string value of length not greater than
the maximum length of a character constant. Leading and trailing blanks are
eliminated and the resulting string must conform to the rules for forming an SQL
