15.00 - EQUALS - 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)

EQUALS

Purpose  

Evaluates two period expressions or derived periods.

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.

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 beginning and ending bound of the first expression is equal to the beginning and ending bound of the second expression; otherwise, the function returns FALSE.
  • If either operand is NULL, the operator returns UNKNOWN.
  • Example  

    Assume that in the employee1 table, created by the following CREATE TABLE statement, period1 and period2 are PERIOD (DATE) columns.

    CREATE TABLE employee1 (
           eid INTEGER NOT NULL,      
           name VARCHAR(100) NOT NULL,
           deptno INTEGER NOT NULL,
           period1(date),
           period2(date)
       ) PRIMARY INDEX(eid);
     

    EID

    Name

    DeptNo

    Period 1

    Period 2

    1

    Adams

    101

    ('2005-02-03', '2006-02-03')

    ('2005-02-03', '2006-02-03')

    2

    Mary

    201

    ('2005-04-02', '2006-01-03')

    ('2006-01-03', '2007-02-03')

    3

    Jones

    301

    ('2004-01-02', '2005-03-05')

    ('2003-03-05', '2004-01-02')

    In the following SQL statement, EQUALS is used with period columns of the employee1 table:

    SELECT eid, name, depno, period1, period2 
    FROM employee1 
    WHERE period1 EQUALS period2;

    The result is:

     

    EID

    Name

    DeptNo

    Period 1

    Period 2

    1

    Adams

    101

    ('2005-02-03', '2006-02-03')

    ('2005-02-03', '2006-02-03')

    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, EQUALS is used with derived period columns of the employee table:

    SELECT eid, name, deptno, jobst1, jobend1, jobst2, jobend2 
    FROM employee 
    WHERE jobdur1 EQUALS jobdur2;

    The result is:

     

    EID

    Name

    DeptNo

    JobSt1

    JobEnd1

    JobSt2

    JobEnd2

    8

    Tim

    801

    DATE'2005-01-01'

    DATE'2007-01-01'

    DATE'2005-01-01'

    'DATE'2007-01-01'