COUNT
Returns the number of rows that have non-null values in a group. Optionally, you can include the asterisk (*) argument to count all input values in a transformation. You can nest only one other aggregate function within COUNT. You can apply a condition to filter rows before counting them.
Use only in Mapping Configuration tasks.
Syntax
COUNT( value [, filter_condition] )
or
COUNT( * [, filter_condition] )
Argument | Required/ Optional | Description |
|---|
value | Required | Any datatype except Binary. Passes the values you want to count. You can enter any valid transformation expression. |
* | Optional | Use to count all rows in a transformation. |
filter_condition | Optional | Limits the rows in the search. The filter condition must be a numeric value or evaluate to TRUE, FALSE, or NULL. You can enter any valid transformation expression. |
Return Value
Integer.
0 if all values passed to this function are NULL (unless you include the asterisk argument).
Nulls
If all values are NULL, the function returns 0.
If you apply the asterisk argument, this function counts all rows, regardless if a column in a row contains a null value.
If you apply the value argument, this function ignores columns with null values.
Group By
COUNT groups values based on group by fields you define in the transformation, returning one result for each group. If there is no group by field COUNT treats all rows as one group, returning one value.
Examples
The following expression counts the items with less than 5 quantity in stock, excluding null values:
COUNT( ITEM_NAME, IN_STOCK < 5 )
ITEM_NAME | IN_STOCK |
|---|
Flashlight | 10 |
NULL | 2 |
Compass | NULL |
Regulator System | 5 |
Safety Knife | 8 |
Halogen Flashlight | 1 |
RETURN VALUE: 1 | |
In this example, the function counted the Halogen flashlight but not the NULL item. The function counts all rows in a transformation, including null values, as illustrated in the following example:
COUNT( *, QTY < 5 )
ITEM_NAME | QTY |
|---|
Flashlight | 10 |
NULL | 2 |
Compass | NULL |
Regulator System | 5 |
Safety Knife | 8 |
Halogen Flashlight | 1 |
RETURN VALUE: 2 | |
In this example, the function counts the NULL item and the Halogen Flashlight. If you include the asterisk argument, but do not use a filter, the function counts all rows that pass into the transformation. For example:
COUNT( * )
ITEM_NAME | QTY |
|---|
Flashlight | 10 |
NULL | 2 |
Compass | NULL |
Regulator System | 5 |
Safety Knife | 8 |
Halogen Flashlight | 1 |
RETURN VALUE: 6 | |