Apache Drill - COALESCE(x, y [ , y ]...)

The following program shows the query for this function −

Query

0: jdbc:drill:zk = local> select coalesce(3,1,7) from (values(1));

Result

+---------+
| EXPR$0  |
+---------+
|   3     |
+-+

Here first arg is non null, so it returns the value 3.