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    MaxCompute:MONTHS_BETWEEN

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    MaxCompute:MONTHS_BETWEEN

    Last Updated:Jul 24, 2023

    Returns the number of months between date1 and date2. This function is an additional function of MaxCompute V2.0.

    Syntax

    double months_between(datetime|timestamp|date|string <date1>, datetime|timestamp|date|string <date2>)

    Parameters

    date1 and date2: required. Values of the DATETIME, TIMESTAMP, DATE, or STRING type. The input values are in the yyyy-mm-dd, yyyy-mm-dd hh:mi:ss, or yyyy-mm-dd hh:mi:ss.ff3 format. If the input values are of the STRING type, the values must include at least the yyyy-mm-dd part and must not contain extra strings.

    Return value

    A value of the DOUBLE type is returned. The return value varies based on the following rules:

    • If date1 is later than date2, a positive value is returned. If date2 is later than date1, a negative value is returned.

    • If date1 and date2 separately correspond to the last days of two months, the return value is an integer that represents the number of months. Otherwise, the return value is calculated by using the following formula: (date1 - date2)/31.

    • If the value of date1 or date2 is null, null is returned.

    Sample data

    This section provides sample source data for you to understand how to use date functions. In this topic, a table named mf_date_fun_t is created and data is inserted into the table. Sample statements: 

    create table if not exists mf_date_fun_t(
    id      int,
    date1   date,
    datetime1   datetime,
    timestamp1 timestamp,
    date2   date,
    datetime2   datetime,
    timestamp2 timestamp,
    date3 string,
    date4 bigint);
insert into mf_date_fun_t values
(1,DATE'2021-11-29',DATETIME'2021-11-29 00:01:00',TIMESTAMP'2021-01-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-20',123456780),
(2,DATE'2021-11-28',DATETIME'2021-11-28 00:02:00',TIMESTAMP'2021-02-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-21',123456781),
(3,DATE'2021-11-27',DATETIME'2021-11-27 00:03:00',TIMESTAMP'2021-03-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-22',123456782),
(4,DATE'2021-11-26',DATETIME'2021-11-26 00:04:00',TIMESTAMP'2021-04-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-23',123456783),
(5,DATE'2021-11-25',DATETIME'2021-11-25 00:05:00',TIMESTAMP'2021-05-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-24',123456784),
(6,DATE'2021-11-24',DATETIME'2021-11-24 00:06:00',TIMESTAMP'2021-06-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-25',123456785),
(7,DATE'2021-11-23',DATETIME'2021-11-23 00:07:00',TIMESTAMP'2021-07-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-26',123456786),
(8,DATE'2021-11-22',DATETIME'2021-11-22 00:08:00',TIMESTAMP'2021-08-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-27',123456787),
(9,DATE'2021-11-21',DATETIME'2021-11-21 00:09:00',TIMESTAMP'2021-09-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-28',123456788),
(10,DATE'2021-11-20',DATETIME'2021-11-20 00:10:00',TIMESTAMP'2021-10-11 00:00:00.123456789',DATE'2021-10-29',DATETIME'2021-10-29 00:00:00',TIMESTAMP'2021-10-11 00:00:00.123456789','2021-11-29',123456789);

    Query data from the mf_date_fun_t table. Sample statement:

    select * from mf_date_fun_t;
-- The following result is returned: 
+------+-------+------------+------------+-------+------------+------------+-------+------------+
| id   | date1 | datetime1  | timestamp1 | date2 | datetime2  | timestamp2 | date3 | date4      |
+------+-------+------------+------------+-------+------------+------------+-------+------------+
| 1    | 2021-11-29 | 2021-11-29 00:01:00 | 2021-01-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-20 | 123456780  |
| 2    | 2021-11-28 | 2021-11-28 00:02:00 | 2021-02-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-21 | 123456781  |
| 3    | 2021-11-27 | 2021-11-27 00:03:00 | 2021-03-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-22 | 123456782  |
| 4    | 2021-11-26 | 2021-11-26 00:04:00 | 2021-04-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-23 | 123456783  |
| 5    | 2021-11-25 | 2021-11-25 00:05:00 | 2021-05-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-24 | 123456784  |
| 6    | 2021-11-24 | 2021-11-24 00:06:00 | 2021-06-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-25 | 123456785  |
| 7    | 2021-11-23 | 2021-11-23 00:07:00 | 2021-07-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-26 | 123456786  |
| 8    | 2021-11-22 | 2021-11-22 00:08:00 | 2021-08-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-27 | 123456787  |
| 9    | 2021-11-21 | 2021-11-21 00:09:00 | 2021-09-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-28 | 123456788  |
| 10   | 2021-11-20 | 2021-11-20 00:10:00 | 2021-10-11 00:00:00.123456789 | 2021-10-29 | 2021-10-29 00:00:00 | 2021-10-11 00:00:00.123456789 | 2021-11-29 | 123456789  |
+------+-------+------------+------------+-------+------------+------------+-------+------------+

    Example: static data

    -- The return value is 3.9495967741935485. 
select months_between('1997-02-28 10:30:00', '1996-10-30');
-- The return value is -3.9495967741935485. 
select months_between('1996-10-30','1997-02-28 10:30:00' );
-- The return value is -3.0. 
select months_between('1996-09-30','1996-12-31');
-- The return value is null. 
select months_between('1996-09-30',null);

    Example: table data

    Calculate the number of months between date values in the timestamp1 and timestamp2 columns based on the Sample data. Sample statement: 

    -- Enable the MaxCompute V2.0 data type edition. Commit this command along with SQL statements. 
set odps.sql.type.system.odps2=true;
select timestamp1, timestamp2, months_between(timestamp1, timestamp2) from mf_date_fun_t;

    The following result is returned: 

    +-------------------------------+-------------------------------+------------+
| timestamp1                    | timestamp2                    | _c2        |
+-------------------------------+-------------------------------+------------+
| 2021-01-11 00:00:00.123456789 | 2021-10-11 00:00:00.123456789 | -9.0       |
| 2021-02-11 00:00:00.123456789 | 2021-10-11 00:00:00.123456789 | -8.0       |
| 2021-03-11 00:00:00.123456789 | 2021-10-11 00:00:00.123456789 | -7.0       |
| 2021-04-11 00:00:00.123456789 | 2021-10-11 00:00:00.123456789 | -6.0       |
| 2021-05-11 00:00:00.123456789 | 2021-10-11 00:00:00.123456789 | -5.0       |
| 2021-06-11 00:00:00.123456789 | 2021-10-11 00:00:00.123456789 | -4.0       |
| 2021-07-11 00:00:00.123456789 | 2021-10-11 00:00:00.123456789 | -3.0       |
| 2021-08-11 00:00:00.123456789 | 2021-10-11 00:00:00.123456789 | -2.0       |
| 2021-09-11 00:00:00.123456789 | 2021-10-11 00:00:00.123456789 | -1.0       |
| 2021-10-11 00:00:00.123456789 | 2021-10-11 00:00:00.123456789 | 0.0        |
+------------+------------+------------+

    Related functions

    MONTHS_BETWEEN is a date function. For more information about functions related to date computing and conversion, see Date functions.