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Date and time types

This topic will describe the DATE, TIME, DATETIME, TIMESTAMP, and DURATION types.

Precautions

  • While inserting time-type property values with DATE, TIME, and DATETIME, NebulaGraph transforms them to a UTC time according to the timezone specified with the timezone_name parameter in the configuration files.

    Note

    To change the timezone, modify the timezone_name value in the configuration files of all NebulaGraph services.

  • date(), time(), and datetime() can convert a time-type property with a specified timezone. For example, datetime("2017-03-04 22:30:40.003000+08:00") or datetime("2017-03-04T22:30:40.003000[Asia/Shanghai]").
  • date(), time(), datetime(), and timestamp() all accept empty parameters to return the current date, time, and datetime.
  • date(), time(), and datetime() all accept the property name to return a specific property value of itself. For example, date().month returns the current month, while time("02:59:40").minute returns the minutes of the importing time.

OpenCypher Compatibility

In nGQL:

  • Year, month, day, hour, minute, second, millisecond, and microsecond are supported, while the nanosecond is not supported.
  • localdatetime() is not supported.
  • Most string time formats are not supported. The exceptions are YYYY-MM-DDThh:mm:ss and YYYY-MM-DD hh:mm:ss.
  • The single-digit string time format is supported. For example, time("1:1:1").

DATE

The DATE type is used for values with a date part but no time part. Nebula Graph retrieves and displays DATE values in the YYYY-MM-DD format. The supported range is -32768-01-01 to 32767-12-31.

The properties of date() include year, month, and day.

TIME

The TIME type is used for values with a time part but no date part. Nebula Graph retrieves and displays TIME values in hh:mm:ss.msmsmsususus format. The supported range is 00:00:00.000000 to 23:59:59.999999.

The properties of time() include hour, minute, and second.

DATETIME

The DATETIME type is used for values that contain both date and time parts. Nebula Graph retrieves and displays DATETIME values in YYYY-MM-DDThh:mm:ss.msmsmsususus format. The supported range is -32768-01-01T00:00:00.000000 to 32767-12-31T23:59:59.999999.

The properties of datetime() include year, month, day, hour, minute, and second.

TIMESTAMP

The TIMESTAMP data type is used for values that contain both date and time parts. It has a range of 1970-01-01T00:00:01 UTC to 2262-04-11T23:47:16 UTC.

TIMESTAMP has the following features:

  • Stored and displayed in the form of a timestamp, such as 1615974839, which means 2021-03-17T17:53:59.
  • Supported TIMESTAMP querying methods: timestamp and timestamp() function.
  • Supported TIMESTAMP inserting methods: timestamp, timestamp() function, and now() function.

  • timestamp() function accepts empty parameters to get the timestamp of the current timezone and also accepts a string type parameter.

    # Return the current time.
nebula> RETURN timestamp();
+-------------+
| timestamp() |
+-------------+
| 1625469277  |
+-------------+

nebula> RETURN timestamp("2022-01-05T06:18:43");
+----------------------------------+
| timestamp("2022-01-05T06:18:43") |
+----------------------------------+
| 1641363523                       |
+----------------------------------+

    Legacy version compatibility

    In NebulaGraph versions earlier than 3.0.0, the time string passed into the timestamp() function could include milliseconds and microseconds. As of version 3.0.0, the time string passed into the timestamp() function cannot include milliseconds and microseconds.

  • The underlying storage data type is int64.

DURATION

The DURATION data type is used to indicate a period of time. Map data that are freely combined by years, months, days, hours, minutes, and seconds indicates the DURATION.

DURATION has the following features:

  • Creating indexes for DURATION is not supported.
  • DURATION can be used to calculate the specified time.

Examples

  1. Create a tag named date1 with three properties: DATE, TIME, and DATETIME.

    nebula> CREATE TAG IF NOT EXISTS date1(p1 date, p2 time, p3 datetime);

  2. Insert a vertex named test1.

    nebula> INSERT VERTEX date1(p1, p2, p3) VALUES "test1":(date("2021-03-17"), time("17:53:59"), datetime("2017-03-04T22:30:40.003000[Asia/Shanghai]"));

  3. Return the content of the property p1 on test1.

    nebula> CREATE TAG INDEX IF NOT EXISTS date1_index ON date1(p1);
nebula> REBUILD TAG INDEX date1_index;
nebula> MATCH (v:date1) RETURN v.date1.p1;
+------------------+
| v.date1.p1.month |
+------------------+
| 3                |
+------------------+

  4. Create a tag named school with the property of TIMESTAMP.

    nebula> CREATE TAG IF NOT EXISTS school(name string , found_time timestamp);

  5. Insert a vertex named DUT with a found-time timestamp of "1988-03-01T08:00:00".

    # Insert as a timestamp. The corresponding timestamp of 1988-03-01T08:00:00 is 573177600, or 573206400 UTC.
nebula> INSERT VERTEX school(name, found_time) VALUES "DUT":("DUT", 573206400);

# Insert in the form of date and time.
nebula> INSERT VERTEX school(name, found_time) VALUES "DUT":("DUT", timestamp("1988-03-01T08:00:00"));

  6. Insert a vertex named dut and store time with now() or timestamp() functions.

    # Use now() function to store time
nebula> INSERT VERTEX school(name, found_time) VALUES "dut":("dut", now());

# Use timestamp() function to store time
nebula> INSERT VERTEX school(name, found_time) VALUES "dut":("dut", timestamp());

You can also use WITH statement to set a specific date and time, or to perform calculations. For example:

nebula> WITH time({hour: 12, minute: 31, second: 14, millisecond:111, microsecond: 222}) AS d RETURN d;
+-----------------+
| d               |
+-----------------+
| 12:31:14.111222 |
+-----------------+

nebula> WITH date({year: 1984, month: 10, day: 11}) AS x RETURN x + 1;
+------------+
| (x+1)      |
+------------+
| 1984-10-12 |
+------------+

nebula> WITH date('1984-10-11') as x, duration({years: 12, days: 14, hours: 99, minutes: 12}) as d \
        RETURN x + d AS sum, x - d AS diff;
+------------+------------+
| sum        | diff       |
+------------+------------+
| 1996-10-29 | 1972-09-23 |
+------------+------------+
Last update: March 13, 2023
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