Interval literal

• 1: Interval subtype units
• 2: Interval qualifier

[ @ ] [-] { quantity subtype-unit }[...] [ AGO ]

1 - Interval subtype units

The following tables lists subtype units that you can specify in an interval literal, divided into major categories:

• Year-month subtype units

• Day-time subtype units

Year-month subtype units

Day-time subtype units

Processing m input

Vertica uses context to interpret the input unit m as months or minutes. For example, the following command creates a one-column table with an interval value:

=> CREATE TABLE int_test(i INTERVAL YEAR TO MONTH);

Given the following INSERT statement, Vertica interprets the interval literal 1y 6m as 1 year 6 months:

=> INSERT INTO int_test VALUES('1y 6m');
 OUTPUT
--------
      1
(1 row)
=> COMMIT;
COMMIT
=> SET INTERVALSTYLE TO UNITS;
SET
=> SELECT * FROM int_test;
        i
-----------------
 1 year 6 months
(1 row)

The following ALTER TABLE statement adds a DAY TO MINUTE interval column to table int_test:

=>  ALTER TABLE int_test ADD COLUMN x INTERVAL DAY TO MINUTE;
ALTER TABLE

The next INSERT statement sets the first and second columns to 3y 20m and 1y 6m, respectively. In this case, Vertica interprets the m input literals in two ways:

• For column i, Vertica interprets the m input as months, and displays 4 years 8 months.

• For column x, Vertica interprets the m input as minutes. Because the interval is defined as DAY TO MINUTE, it converts the inserted input value 1y 6m to 365 days 6 minutes:

=> INSERT INTO int_test VALUES ('3y 20m', '1y 6m');
 OUTPUT
--------
      1
(1 row)

=> SELECT * FROM int_test;
        i         |        x
------------------+-----------------
 1 year 6 months  |
 4 years 8 months | 365 days 6 mins
(2 rows)

2 - Interval qualifier

Specifies how to interpret and format an interval literal for output, and optionally sets precision. Interval qualifiers are composed of one or two units:

unit [ TO unit ] [ (p) ]

where:

• unit specifies a day-time or year-month subtype.

• p specifies precision, an integer between 0 and 6.

  Note

  Precision only applies to SECOND units, specifying the number of decimal digits to show after the seconds value decimal point. The default precision for SECOND is 6.

  When SECOND is the second unit of a qualifier—for example, DAY TO SECOND or MINUTE TO SECOND—it has a precision of 2 places before the decimal point.

  For example:

  => SELECT INTERVAL '6 122.538987' MINUTE TO SECOND (5);
    ?column?
  -------------
   08:02.53899
  (1 row)
  

  For details, see Specifying interval precision.

If an interval omits an interval qualifier, the default is DAY TO SECOND(6).

Interval qualifiers are divided into two categories:

• day-time

• year-month

Day-time interval qualifiers

Year-month interval qualifiers

YEAR

Unconstrained

MONTH

Months within year

YEAR TO MONTH

Span of years and months

=> SELECT INTERVALYM '1 2';
 ?column?
----------
 1-2
(1 row)
=> SELECT INTERVAL '1 2' YEAR TO MONTH;
?column?
1-2
(1 row)

Examples

See Controlling interval format.