# SQL expression processor

Writes the result of one or more custom SQL expressions in a new column.

The SQL expression processor lets you write simple or complex SQL expressions to process data in a new column of your source dataset. You can add more SQL expressions with the add icon.

## SQL expression properties

Properties to configure to create a new column and apply SQL expressions on it. Each expression creates a new column.

Configuration

| Property | Configuration |
| --- | --- |
| Name | Enter the name of the new column on which the SQL expression will be applied. |
| Type | Select the data type of the column.<br><br>Depending on which data type you select you may also need to set more column properties, for example, Precision, Scale, or Length. |
| Nullable | Select if you want the column to be nullable. |
| SQL expression | Either enter a simple SQL expression in the text box, or click the Expression builder icon to open the expression builder. In the expression builder, you can:<br><br><ul> <li> <p>Enter complex SQL expressions in the <span>Build expression</span> text box. You can select the column names on the left panel to auto-complete your expression.</p> </li> <li> <p>Extract all parameters used in the SQL expression in the <span>Extract parameters</span> area, and test them with custom values.</p> </li> <li> <p>Test your SQLexpression in the <span>Test expression</span> area.</p> </li> </ul> |

To rename the processor, click the ![Edit](https://help.qlik.com/en-US/cloud-services/Subsystems/Hub/Content/Resources/Images/TransformationFlow/processor-select-columns-edit_26x24.png)Edit icon that is displayed when hovering over the default name of the processor.

To edit its description, click the ![Edit](https://help.qlik.com/en-US/cloud-services/Subsystems/Hub/Content/Resources/Images/TransformationFlow/processor-select-columns-edit_26x24.png)Edit icon that is displayed when hovering over Description.