# lag


The `lag` function calculates the lag (previous) value for a measure based on specified partitions and sorts.

`lag` is supported for use with analyses based on SPICE and direct query data sets.

## Syntax


The brackets are required. To see which arguments are optional, see the following descriptions.

```
lag
(
lag
(
 measure
 ,[ sortorder_field ASC_or_DESC, ... ] 
 ,lookup_index
 ,[ partition_field, ... ] 
)] 
)
```

## Arguments


*measure*   
The measure that you want to get the lag for. This can include an aggregate, for example `sum({Sales Amt})`.

*sort order field*   
One or more measures and dimensions that you want to sort the data by, separated by commas. You can specify either ascending (**ASC**) or descending (**DESC**) sort order.   
Each field in the list is enclosed in \$1\$1 (curly braces), if it is more than one word. The entire list is enclosed in [ ] (square brackets).

*lookup index*   
The lookup index can be positive or negative, indicating a following row in the sort (positive) or a previous row in the sort (negative). The lookup index can be 1–2,147,483,647. For the engines MySQL, MariaDB, and Amazon Aurora MySQL-Compatible Edition, the lookup index is limited to just 1.

 *partition field*   
(Optional) One or more dimensions that you want to partition by, separated by commas.   
Each field in the list is enclosed in \$1\$1 (curly braces), if it is more than one word. The entire list is enclosed in [ ] (square brackets).

## Example


The following example calculates the previous `sum(sales)`, partitioned by the state of origin, in the ascending sort order on `cancellation_code`.

```
lag
(
     sum(Sales), 
     [cancellation_code ASC], 
     1, 
     [origin_state_nm]
)
```

The following example uses a calculated field with `lag` to display sales amount for the previous row next to the amount for the current row, sorted by `Order Date`. The fields in the table calculation are in the field wells of the visual.

```
lag(
     sum({Sales}),
     [{Order Date} ASC],
     1
)
```

The following screenshot shows the results of the example.

![\[alt text not found\]](http://docs.amazonaws.cn/en_us/quick/latest/userguide/images/lagCalc.png)


The following example uses a calculated field with `lag` to display the sales amount for the previous row next to the amount for the current row, sorted by `Order Date` partitioned by `Segment`.

```
lag
	(
		sum(Sales),
		[Order Date ASC],
		1, [Segment]
	)
```

The following screenshot shows the results of the example.

![\[alt text not found\]](http://docs.amazonaws.cn/en_us/quick/latest/userguide/images/lagCalc2.png)