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new 9411a50 add date_diff function
9411a50 is described below
commit 9411a50b57bff0d146bbd3993ef575010b09877d
Author: Bridget Bevens <[email protected]>
AuthorDate: Tue Jan 15 15:02:35 2019 -0800
add date_diff function
---
.../030-date-time-functions-and-arithmetic.md | 126 +++++++++++++++++++--
1 file changed, 117 insertions(+), 9 deletions(-)
diff --git
a/_docs/sql-reference/sql-functions/030-date-time-functions-and-arithmetic.md
b/_docs/sql-reference/sql-functions/030-date-time-functions-and-arithmetic.md
index 241cf96..5ed65c2 100644
---
a/_docs/sql-reference/sql-functions/030-date-time-functions-and-arithmetic.md
+++
b/_docs/sql-reference/sql-functions/030-date-time-functions-and-arithmetic.md
@@ -1,6 +1,6 @@
---
title: "Date/Time Functions and Arithmetic"
-date: 2019-01-04
+date: 2019-01-15
parent: "SQL Functions"
---
@@ -16,6 +16,7 @@ This section covers the Drill [time zone
limitation]({{site.baseurl}}/docs/data-
[CURRENT_TIME]({{ site.baseurl
}}/docs/date-time-functions-and-arithmetic/#other-date-and-time-functions)
| TIME
[CURRENT_TIMESTAMP]({{ site.baseurl
}}/docs/date-time-functions-and-arithmetic/#other-date-and-time-functions) |
TIMESTAMP
[DATE_ADD]({{ site.baseurl
}}/docs/date-time-functions-and-arithmetic/#date_add)
| DATE, TIMESTAMP
+[DATE_DIFF]({{ site.baseurl
}}/docs/date-time-functions-and-arithmetic/#date_diff)
| DATE, TIMESTAMP
[DATE_PART]({{ site.baseurl
}}/docs/date-time-functions-and-arithmetic/#date_part)
| DOUBLE
[DATE_SUB]({{ site.baseurl
}}/docs/date-time-functions-and-arithmetic/#date_sub)
| DATE, TIMESTAMP
[LOCALTIME]({{ site.baseurl
}}/docs/date-time-functions-and-arithmetic/#other-date-and-time-functions)
| TIME
@@ -79,12 +80,11 @@ For information about how to read the interval data, see
the [Interval section](
## DATE_ADD
Returns the sum of a date/time and a number of days/hours, or of a date/time
and date/time interval.
-### DATE_ADD Syntax
-
-`DATE_ADD(keyword literal, integer)`
-`DATE_ADD(keyword literal, interval expr)`
-`DATE_ADD(column, integer)`
-`DATE_ADD(column, interval expr)`
+### DATE_ADD Syntax
+- `DATE_ADD(keyword literal, integer)`
+- `DATE_ADD(keyword literal, interval expr)`
+- `DATE_ADD(column, integer)`
+- `DATE_ADD(column, interval expr)`
*keyword* is the word date, time, or timestamp.
*literal* is a date, time, or timestamp literal. For example, a date in
yyyy-mm-dd format enclosed in single quotation marks.
@@ -193,7 +193,116 @@ Add 1 day 2 and 1/2 hours and 45.100 seconds to the time
22:55:55.
+---------------+
| 01:26:40.100 |
+---------------+
- 1 row selected (0.106 seconds)
+ 1 row selected (0.106 seconds)
+
+##DATE_DIFF
+Returns the difference of a date/time and a number of days/hours, or of a
date/time and date/time interval.
+
+**NOTE:** You can use the Hive `DATEDIFF()` function in Drill with string
values, as shown:
+
+ SELECT DATEDIFF('1996-03-01', '1997-02-10 17:32:00.0'), TIMEOFDAY()
FROM (VALUES(1));
+ +---------+----------------------------------------------+
+ | EXPR$0 | EXPR$1 |
+ +---------+----------------------------------------------+
+ | -346 | 2019-01-15 14:54:21.455 America/Los_Angeles |
+ +---------+----------------------------------------------+
+
+However, for date and timestamp values, use the `DATE_DIFF` function and
convert the interval returned to a number, as shown:
+
+ SELECT TO_NUMBER(DATE_DIFF(DATE '1996-03-01', TIMESTAMP '1997-02-10
17:32:00.0'), '#'), TIMEOFDAY() FROM (VALUES(1));
+ +---------+----------------------------------------------+
+ | EXPR$0 | EXPR$1 |
+ +---------+----------------------------------------------+
+ | -346.0 | 2019-01-15 14:52:15.247 America/Los_Angeles |
+ +---------+----------------------------------------------+
+
+### DATE_DIFF Syntax
+- `DATE_DIFF(keyword literal, integer)`
+- `DATE_DIFF(keyword literal, interval expr)`
+- `DATE_DIFF(column, integer)`
+- `DATE_DIFF(column, interval expr)`
+
+*keyword* is the word date, time, or timestamp.
+*literal* is a date, time, or timestamp literal. For example, a date in
yyyy-mm-dd format enclosed in single quotation marks.
+*integer* is a number of days to subtract from the date/time.
+*column* is date, time, or timestamp data in a data source column.
+*interval* is the keyword interval.
+*expr* is an interval expression, such as the name of a data source column
containing interval data.
+
+###DATE_DIFF Examples
+The following examples show how to use the syntax variations.
+
+**DATE_DIFF(keyword literal, integer) Syntax Example**
+
+Subtract two days from the date May 15, 2015.
+
+ SELECT DATE_DIFF(date '2015-05-15', 2) FROM (VALUES(1));
+ +-------------+
+ | EXPR$0 |
+ +-------------+
+ | 2015-05-13 |
+ +-------------+
+
+**DATE_DIFF(keyword literal, interval expr) Syntax Example**
+
+Using the example data from the ["Casting
Intervals"]({{site.baseurl}}/docs/data-type-conversion/#casting-intervals)
section, subtract intervals from the `intervals.json` file from a literal
timestamp. Create an interval expression that casts the INTERVALDAY_col column,
which contains P1D, P2D, and P3D, to a timestamp.
+
+ SELECT DATE_DIFF(timestamp '2015-04-15 22:55:55', CAST(INTERVALDAY_col
as interval second)) FROM dfs.`/home/bee/intervals.json`;
+ +------------------------+
+ | EXPR$0 |
+ +------------------------+
+ | 2015-04-14 22:55:55.0 |
+ | 2015-04-13 22:55:55.0 |
+ | 2015-04-12 22:55:55.0 |
+ +------------------------+
+
+The query output is the difference of the timestamp and 1, 2, and 3 days
corresponding to P1D, P2D, and P3D.
+
+**DATE_DIFF(column, integer) Syntax Example**
+
+Subtract two days from the value in the birth_date column.
+
+ SELECT DATE_DIFF(CAST(birth_date AS date), 2) as a FROM
cp.`employee.json` LIMIT 1;
+ +-------------+
+ | a |
+ +-------------+
+ | 1961-08-24 |
+ +-------------+
+
+**DATE_DIFF(column, interval expr) Syntax Example**
+
+Subtract a 10 hour interval from the hire dates of employees listed in the
`employee.json` file, which Drill includes in the installation.
+
+Cast the hire_dates of the employees 578 and 761 to a timestamp, and subtract
10 hours from the hire_date timestamp. Drill reads data from JSON as VARCHAR;
therefore, cast the hire_date to the TIMESTAMP type.
+
+ SELECT DATE_DIFF(CAST(hire_date AS TIMESTAMP), interval '10' hour) FROM
cp.`employee.json` where employee_id IN( '578','761');
+ +------------------------+
+ | EXPR$0 |
+ +------------------------+
+ | 1995-12-31 14:00:00.0 |
+ | 1997-12-31 14:00:00.0 |
+ +------------------------+
+
+**DATE_DIFF(keyword literal, integer) Syntax Example**
+
+Subtract 1 year and 2 months from the timestamp 2015-04-15 22:55:55.
+
+ SELECT DATE_DIFF(timestamp '2015-04-15 22:55:55', interval '1-2' year
to month) FROM (VALUES(1));
+ +------------------------+
+ | EXPR$0 |
+ +------------------------+
+ | 2014-02-15 22:55:55.0 |
+ +------------------------+
+
+Subtract 1 day 2 and 1/2 hours and 45.100 seconds from the time 22:55:55.
+
+ SELECT DATE_DIFF(time '22:55:55', interval '1 2:30:45.100' day to
second) FROM (VALUES(1));
+ +---------------+
+ | EXPR$0 |
+ +---------------+
+ | 20:25:09.900 |
+ +---------------+
+
## DATE_PART
Returns a field of a date, time, timestamp, or interval.
@@ -636,7 +745,6 @@ TIMESTAMPDIFF(*time\_unit, datetime\_expression1,
datetime\_expression2*)
###TIMESTAMPDIFF Usage Notes
- *datetime\_expression* is a column or literal with date, time, or timestamp
values.
- *time\_unit* is any of the following: Nanosecond, Microsecond, Second,
Minute, Hour, Day, Month, Year, Week, Quarter
-- *interval* is the amount of *time\_unit* to add.
- You can include two date expressions, or one date expression with one
datetime expression.
- Drill uses the *time\_unit* to infer the return type.
- You can include the `SQL_TSI_` prefix with the any of the supported time
units, as shown:
