BEGIN
Purpose
Returns the beginning bound of a Period expression or a derived period.
Syntax
where:
|
Syntax element... |
Specifies... |
|
period_expression |
any expression that evaluates to a Period data type. |
|
derived_period |
any expression that evaluates to a derived period. |
Return Value
The result data type of the BEGIN function is same as the element type of the Period expression or the data type of the begin column if the argument is a derived period column. If the argument is NULL, the result is NULL.
Format and Title
The format is the default format for the element type of the Period expression or the format of the begin column if the argument is a derived period column.
Error Conditions
If the argument does not have a Period data type, an error is reported.
Example
BEGIN returns the beginning bound of a Period data type.
SELECT * FROM employee WHERE BEGIN(period1) = DATE '2004-06-19';
Assume the query is executed on the following employee table where period1 is a PERIOD(DATE) column:
ename dept period1
----- ----------- ----------------------------
Jones Sales ('2004-01-02', '2004-01-05')
Adams Marketing ('2004-06-19', '2005-02-09')
Mary Development ('2004-06-19', '2005-01-05')
Simon Sales ('2004-06-22', '2005-01-07')
The result is:
ename dept period1
----- ----------- ----------------------------
Adams Marketing ('2004-06-19', '2005-02-09')
Mary Development ('2004-06-19', '2005-01-05')
Example
BEGIN returns the beginning bound (jdbegin) of a derived period called jobduration created using the following SQL statement:
CREATE TABLE employee(id INTEGER,
name VARCHAR(50),
jdbegin DATE NOT NULL FORMAT 'YYYY-MM-DD',
jdend DATE NOT NULL FORMAT 'YYYY-MM-DD',
PERIOD FOR jobduration(jdbegin,jdend)
)PRIMARY INDEX(id);
The following SQL statements:
INSERT INTO employee(1025,'John',DATE'2011-01-02',DATE'2012-05-02');
SELECT BEGIN (jobduration) FROM employee;
returns:
jdbegin
__________
2011-01-02