Build ADF expressions

When to use the builder

Open Tools → ADF Expression Builder after your specification has its source tables and joins. ETLGen uses the known columns and data types to produce safer casts.

Choose a transformation

• Derived Column changes or creates a value, similar to a SELECT expression.
• Conditional Split routes rows, similar to a search condition in WHERE logic.

Generate the expression

Enter a T-SQL expression or condition and select Generate Expression. Review the output, especially casts and null behavior, before placing it in the data flow.

For example, text comparisons may require an explicit toString() conversion in ADF. The exact expression depends on the source data type.