MEETS
Purpose
Evaluates two period expressions, or derived periods, or DateTime expressions and evaluates to TRUE, FALSE, or UNKNOWN.
Syntax
where:
|
Syntax element... |
Specifies... |
|
period_expression |
any expression that evaluates to a Period data type. Note: The Period expression specified must be comparable with the other expression. Implicit casting to a Period data type is not supported. |
|
datetime_expression |
any expression that evaluates to a DATE, TIME, or TIMESTAMP data type. |
|
derived_period |
any expression that evaluates to a derived period. |
Result Value
Error Conditions
If either expression evaluates to a data type other than a Period or DateTime, an error is reported.
If the expressions are not comparable, an error is reported.
Example
Assume the following query is executed on the employee table where period1 and period2 are PERIOD(DATE) columns:
SELECT * FROM employee WHERE period2 MEETS period1;
|
ename |
period1 |
period2 |
|
Adams |
('2005-02-03', '2006-02-03') |
('2005-02-03', '2006-02-03') |
|
Mary |
('2005-04-02', '2006-01-03') |
('2005-02-03', '2006-02-03') |
|
Jones |
('2004-01-02', '2004-03-05') |
('2004-03-05', '2004-10-07') |
|
Randy |
('2004-01-02', '2004-03-05') |
('2004-03-07', '2004-10-07') |
|
Simon |
? |
('2005-02-03', '2005-07-27') |
The result is:
|
ename |
period1 |
period2 |
|
Jones |
('2004-01-02','2004-03-05') |
('2004-03-05', '2004-10-07') |
Example
Assume that in the employee table, created by the following CREATE TABLE statement, jobdur1 and jobdur2 are derived period columns.
CREATE TABLE employee (
eid INTEGER NOT NULL,
name VARCHAR(100) NOT NULL,
deptno INTEGER NOT NULL,
jobst1 DATE NOT NULL,
jobend1 DATE NOT NULL,
PERIOD FOR jobdur1(jobst1, jobend1),
jobst2 DATE NOT NULL,
jobend2 DATE NOT NULL,
PERIOD FOR jobdur2(jobst2, jobend2)
) PRIMARY INDEX(eid);
|
EID |
Name |
DeptNo |
JobSt1 |
JobEnd1 |
JobSt2 |
JobEnd2 |
|
1 |
Tom |
101 |
DATE'2001-01-01' |
DATE'2004-01-01' |
DATE'2005-01-01' |
DATE'2006-01-01' |
|
2 |
Rick |
201 |
DATE'2005-01-01' |
DATE'2006-01-01' |
DATE'2001-01-01' |
DATE'2004-01-01' |
|
3 |
Joo |
301 |
DATE'2005-01-01' |
DATE'2006-01-01' |
DATE'2006-01-01' |
DATE'2007-01-01' |
|
4 |
Tam |
401 |
DATE'2001-01-01' |
DATE'2006-01-01' |
DATE'2002-01-01' |
DATE'2004-01-01' |
|
5 |
Pat |
501 |
DATE'2005-01-01' |
DATE'2007-01-01' |
DATE'2006-01-01' |
DATE'2008-01-01' |
|
6 |
Jack |
601 |
DATE'2005-01-01' |
DATE'2007-01-01' |
DATE'2007-01-01' |
DATE'2008-01-01' |
|
7 |
Yu |
701 |
DATE'2005-01-01' |
DATE'2007-01-01' |
DATE'2004-01-01' |
DATE'2005-01-01' |
|
8 |
Tim |
801 |
DATE'2005-01-01' |
DATE'2007-01-01' |
DATE'2005-01-01' |
DATE'2007-01-01' |
In the following SQL statement, MEETS is used with derived period columns of the employee table:
SELECT eid, name, deptno, jobst1, jobend1, jobst2, jobend2
FROM employee
WHERE jobdur1 MEETS jobdur2;
The result is:
|
EID |
Name |
DeptNo |
JobSt1 |
JobEnd1 |
JobSt2 |
JobEnd2 |
|
3 |
Joo |
301 |
DATE'2005-01-01' |
DATE'2006-01-01' |
DATE'2006-01-01' |
DATE'2007-01-01' |
|
6 |
Jack |
601 |
DATE'2005-01-01' |
DATE'2007-01-01' |
DATE'2007-01-01' |
DATE'2008-01-01' |
|
7 |
Yu |
701 |
DATE'2005-01-01' |
DATE'2007-01-01' |
DATE'2004-01-01' |
DATE'2005-01-01' |