I'm trying to retrieve all(*) columns from a MongoDB object with Apache Drill expression SQL:
`_id`.`$oid`
Background: I'm using Apache Drill to query MongoDB collections. By default, Drill retrieves the ObjectId values in a different format than the stored in the database. For example:
Mongo: ObjectId(“59f2c3eba83a576fe07c735c”)
Drill query result: [B@3149a…]
In order to get the data in String format (59f2c3eba83a576fe07c735c) from the object, I changed the Drill config "store.mongo.bson.record.reader" to "false".
ALTER SESSION SET store.mongo.bson.record.reader = false
Drill query result after config set to false:
select * from calc;
+--------------------------------------+---------+
| _id | name |
+--------------------------------------+---------+
| {"$oid":"5cb0e161f0849231dfe16d99"} | thiago |
+--------------------------------------+---------+
Running a query by _id:
select `o`.`_id`.`$oid` , `o`.`name` from mongo.od_teste.calc o where `o`.`_id`.`$oid`='5cb0e161f0849231dfe16d99';
Result:
+---------------------------+---------+
| EXPR$0 | name |
+---------------------------+---------+
| 5cb0e161f0849231dfe16d99 | thiago |
+---------------------------+---------+
For an object with a few columns like the one above (_id, name) it's ok to specify all the columns in the select query by id. However, in my production database, the objects have a "hundred" of columns.
If I try to query all (*) columns from the collection, this is the result:
select `o`.* from mongo.od_teste.calc o where `o`.`_id`.`$oid`='5cb0e161f0849231dfe16d99';
or
select * from mongo.od_teste.calc o where `o`.`_id`.`$oid`='5cb0e161f0849231dfe16d99';
+-----+
| ** |
+-----+
+-----+
No rows selected (6.112 seconds)
Expected result: Retrieve all columns from a MongoDB collection instead of declaring all of them on the SQL query.
