Compare custom parameters - DataWorks - Alibaba Cloud Documentation Center

Custom parameters are classified into built-in parameters, ${...} parameters, $[...] parameters, and constants. The values of custom parameters of each type are in specific formats. This topic describes the differences between the value formats of different types of custom parameters.

How different custom parameters are used

For example, the current date is November 1, 2021, and a node is scheduled to run at 00:00 every day. The following table describes how different customer parameters are assigned values.

Note

In this example, the parameters are referenced in the pt=${datetime} format in the code.

Parameter	Description	Assignment	Replacement result
`${yyyymmdd}`	Obtains the data timestamp of the node.	`datetime=${yyyymmdd}`	`datetime=20211031`
`$[yyyymmddhh24miss]`	Obtains the time when the node is scheduled to run, which is accurate to seconds.	`datetime=$[yyyymmddhh24miss]`	`datetime=20211101000000`
`$bizdate`	Obtains the data timestamp of the node.	`datetime=$bizdate`	`datetime=20211031`
`$cyctime`	Obtains the time when the node is scheduled to run, which is accurate to seconds.	`datetime=$cyctime`	`datetime=20211101000000`
`$gmtdate`	Obtains the current date, which is accurate to days.	`datetime=$gmtdate`	`datetime=20211101`
`$bizmonth`	Obtains the month specified by the data timestamp of the node.	`datetime=$bizmonth`	If the month specified by the data timestamp is the current month, the value of the `$bizmonth` parameter is the previous month. If the month specified by the data timestamp is not the current month, the value of the `$bizmonth` parameter is the month specified by the data timestamp. In this example, the current date is `November 1, 2021`.

Differences between ${...} and $[...] parameters

The following table describes the differences between the ${...} and $[...] parameters.

Item	${…} parameter	$[…] parameter
Benchmark	The value of the `$bizdate` parameter is used as a benchmark to run nodes. The `$bizdate` parameter specifies the data timestamp. By default, the date specified by the data timestamp is one day earlier than the current date.	The value of the `$cyctime` parameter is used as a benchmark to run nodes. The `$cyctime` parameter specifies the time when a node is scheduled to run. For example, the value `yyyy-mm-dd 00:30:00` indicates `00:30` on the current day.
Data backfill	The parameter is replaced with the selected data timestamp.	During data backfilling, the parameter is replaced with the date that is `one day after the date specified by the selected data timestamp`. For example, `20220315` is the date specified by the selected data timestamp for data backfilling. In this case, the date specified by the value of the `$cyctime` parameter is `20220316`.
Time granularity	The value is accurate to days. If you want to specify a time that is N years or months ago, we recommend that you use a ${...} parameter.	The value is accurate to seconds. If you want to specify a time that is N hours or minutes ago, we recommend that you use a $[...] parameter. For example, `$[yyyymmdd-1-1/24]` indicates the time that is one hour before the scheduling time of a node on the previous day. Note `${yyyy-mm-dd-1/24}` is not supported. We recommend that you use `$[yyyy-mm-dd-1-1/24]`.

In this example, an ODPS SQL node is used, and the current time is 10:30:00 on July 20, 2021. The following table describes how to use ${...} and $[...] parameters.

Time to obtain	${…} parameter	$[…] parameter
Year: 2021	Assignment: `datetime=${yyyy}` Reference in code: `pt=${datetime}` Replacement result: `pt=${yyyy}=2021`	Assignment: `datetime=$[yyyy]` Reference in code: `pt=${datetime}` Replacement result: `pt=$[yyyy]=2021`
Year: 21	Assignment: `datetime=${yy}` Reference in code: `pt=${datetime}` Replacement result: `pt=${yy}=21`	Assignment: `datetime=$[yy]` Reference in code: `pt=${datetime}` Replacement result: `pt=$[yy]=21`
Year: 2020	Assignment: `datetime=${yyyy-1}` Reference in code: `pt=${datetime}` Replacement result: `pt=${yyyy-1}=2020`	Not supported
Month: 07	Assignment: `datetime=${mm}` Reference in code: `pt=${datetime}` Replacement result: `pt=${mm}=07`	Assignment: `datetime=$[mm]` Reference in code: `pt=${datetime}` Replacement result: `pt=$[mm]=07`
Day: 20	Assignment: `datetime=${dd}` Reference in code: `pt=${datetime}` Replacement result: `pt=${dd}=20`	Assignment: `datetime=$[dd]` Reference in code: `pt=${datetime}` Replacement result: `pt=$[dd]=20`
Date: 2021-06-20	Assignment: `datetime=${yyyy-mm-dd-29}` Reference in code: `pt=${datetime}` Replacement result: `pt=${yyyy-mm-dd-29}=2021-06-20`	Assignment: `datetime=$[add_months(yyyymmdd,-1)]` Reference in code: `pt=${datetime}` Replacement result: `pt=$[add_months(yyyymmdd,-1)]=2021-06-20`
Date: 2021-07-19	Assignment: `datetime=${yyyy-mm-dd}` Reference in code: `pt=${datetime}` Replacement result: `pt=${yyyy-mm-dd}=2021-07-19`	Assignment: `datetime=$[yyyy-mm-dd-1]` Reference in code: `pt=${datetime}` Replacement result: `pt=$[yyyy-mm-dd-1]=2021-07-19`
Date: 2020-07-20	Assignment: `datetime=${yyyy-mm-dd-364}` Reference in code: `pt=${datetime}` Replacement result: `pt=${yyyy-mm-dd-364}=2020-07-20`	Assignment: `datetime=$[add_months(yyyymmdd,-121)]` Reference in code: `pt=${datetime}` Replacement result: `pt=$[add_months(yyyymmdd,-121)]=2020-07-20`
Time: 10:30:00	Not supported	Assignment: `datetime=$[hh24:mi:ss]` Reference in code: `pt=${datetime}` Replacement result: `pt=$[hh24:mi:ss]=10:30:00`
Time: 2021-07-20 10:30:00	Not supported	Assignment: `datetime1=$[yyyy-mm-dd] datetime2=$[hh24:mi:ss]` Note You must specify two custom variables datetime1 and datetime2, and separate the key-value pairs of the variables with a space. Reference in code: `pt=${datetime1} ${datetime2}` Replacement result: `datetime1=$[yyyy-mm-dd]=2021-07-20` `datetime2=$[hh24:mi:ss]=10:30:00` `pt=2021-07-20 10:30:00`
Time: 2021-07-20 10:29:00	Not supported	Assignment: `datetime1=$[yyyy-mm-dd] datetime2=$[hh24:mi:ss-1/24/60]` Note You must customize two variables datetime1 and datetime2, and separate the key-value pairs of the variables with a space. Reference in code: `pt=${datetime1} ${datetime2}` Replacement result: `datetime1=$[yyyy-mm-dd]=2021-07-20` `datetime2=$[hh24:mi:ss-1/24/60]=10:29:00` `pt=2021-07-20 10:29:00`
Time: 2021-07-20 09:30:00	Not supported	Assignment: `datetime1=$[yyyy-mm-dd] datetime2=$[hh24:mi:ss-1/24]` Note You must customize two variables datetime1 and datetime2, and separate the key-value pairs of the variables with a space. Reference in code: `pt=${datetime1} ${datetime2}` Replacement result: `datetime1=$[yyyy-mm-dd]=2021-07-20` `datetime2=$[hh24:mi:ss-1/24]=09:30:00` `pt=2021-07-20 09:30:00`
Time: 2021071910:30:00	Not supported	Assignment: `datetime=$[yyyymmddhh24miss-1]` Reference in code: `pt=${datetime}` Replacement result: `datetime=$[yyyymmddhh24miss-1]=2021071910:30:00` `pt=2021071910:30:00`
Time: 20210719 10:30:00	Not supported	Important Spaces are not supported in one assignment expression. You can use two scheduling parameters and separate the assignment expressions of the two parameters with a space. Assignment: `datetime1=$[yyyymmdd-1] datetime2=$[hh24:mi:ss]` Note You must customize two variables datetime1 and datetime2, and separate the key-value pairs of the variables with a space. Reference in code: `pt=${datetime1} ${datetime2}` Replacement result: `datetime1=$[yyyymmdd-1]=2021-07-19` `datetime2=$[hh24:mi:ss]=10:30:00` `pt=20210719 10:30:00`