grid > source > query > select > columns

The <columns> element wraps all the columns to be selected from the table that was specified with the <from> element.

It takes zero or more <column> or <expression> child elements.

If no <columns> are configured, all columns will be included in the result set (e.g. SELECT * FROM table).

Example:

<columns>
    <column name="status" as="order_status"/>
    <expression as="count">COUNT(*)</expression>
</columns>