For example, you might have data on dates that customers opened and closed accounts with your company. You want to inspect the data to ensure that the dates in your system are valid. If the dates are not valid, you want to issue a warning.

To inspect the data, you can create an Expression transformation and configure the following ports:

The input port

SignUpDate

is the date that a customer opened an account. The input port

CancelDate

is the date that a customer closed an account.

The variable port

CompareDates

returns -1, 0, or 1 depending on whether the value in the port

CancelDate

is earlier or later than the value in the port

SignUpDate

. The port

GenerateAlert

returns 'Warning' if the value in the port

CompareDates

is 1.

For the variable port

CompareDates

, you can configure an expression parameter with the following default value:

DATE_COMPARE(SignUpDate,CancelDate)

To nest the expression parameter that you use for the variable port

CompareDates

in the expression parameter for the output port

GenerateAlert

, you can configure an expression parameter with the following default value:

IIF(CompareDates=1,'Warning')