Using the IN Operator in a CAML Query

The In operator is used in an SQL query allows you to specify multiple values in a
WHERE clause. The CAML query language also uses the IN operator, in place of using multiple ORs, to return multiple values of a column.

<In><FieldRef Name='Col1'/>
    <Values>
        <Value Type='Text'>A</Value>
        <Value Type='Text'>B</Value>
        <Value Type='Text'>C</Value>
    </Values>
</In>