15.00 - MEETS - Teradata Database

Teradata Database SQL Functions, Operators, Expressions, and Predicates

Product
Teradata Database
Release Number
15.00
Content Type
Programming Reference
Publication ID
B035-1145-015K
Language
English (United States)
Last Update
2018-09-24

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

  • If both expressions have a Period data type or a derived period, the function returns TRUE if the ending bound of the first expression is equal to the beginning bound of the second expression or the ending bound of the second expression is equal to the beginning bound of the first expression; otherwise, the function returns FALSE.
  • If one expression is a Period data type and the other expression is a DateTime expression, the function returns TRUE if the ending bound of the Period expression is equal to the DateTime expression or if the DateTime expression plus one granule is equal to the beginning bound of the Period expression; otherwise, the function returns FALSE.
  • If either expression is NULL, the function returns UNKNOWN.
  • 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'