ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
SQL support in local databases
When a SELECT appears within an expression but is not the right operand of an IN operator, then the first row of the
result of the SELECT becomes the value used in the expression. If the SELECT yields more than one result row, all rows
after the first are ignored. If the SELECT yields no rows, then the value of the SELECT is NULL.
CAST expression
A CAST expression changes the data type of the value specified to the one given. The type specified can be any nonempty
type name that is valid for the type in a column definition of a CREATE TABLE statement. See Data type
support for details.
Additional expression elements
The following SQL elements can also be used in expressions:
Built-in functions: Aggregate functions, Scalar functions, and Date and time formatting functions
Operators
Parameters
Built-in functions
The built-in functions fall into three main categories:
Aggregate functions
Scalar functions
Date and time functions
In addition to these functions, there is a special function RAISE() that is used to provide notification of an error in the
execution of a trigger. This function can only be used within the body of a CREATE TRIGGER statement. For
information on the RAISE() function, see CREATE TRIGGER > RAISE().
Like all keywords in SQL, function names are not case sensitive.
Aggregate functions
Aggregate functions perform operations on values from multiple rows. These functions are primarily used in SELECT
statements in conjunction with the GROUP BY clause.
AVG(X) Returns the average value of all non-NULL X within a group. String and BLOB values that do not
look like numbers are interpreted as 0. The result of AVG() is always a floating point value even
if all inputs are integers.
COUNT(X) The first form returns a count of the number of times that X is not NULL in a group. The second
COUNT(*) form (with the * argument) returns the total number of rows in the group.
MAX(X) Returns the maximum value of all values in the group. The usual sort order is used to determine
the maximum.
MIN(X) Returns the minimum non-NULL value of all values in the group. The usual sort order is used
to determine the minimum. If all values in the group are NULL, NULL is returned.
SUM(X)
Returns the numeric sum of all non-NULL values in the group. If all of the values are NULL then
SUM() returns NULL, and TOTAL() returns 0.0. The result of TOTAL() is always a floating point
TOTAL(X)
value. The result of SUM() is an integer value if all non-NULL inputs are integers. If any input to
SUM() is not an integer and not NULL then SUM() returns a floating point value. This value
might be an approximation to the true sum.
In any of the preceding aggregate functions that take a single argument, that argument can be preceded by the keyword
DISTINCT. In that case, duplicate elements are filtered before being passed into the aggregate function. For example,
the function call COUNT(DISTINCT x) returns the number of distinct values of column X instead of the total number
of non-NULL values in column x.
Last updated 6/6/2012
1108