Summary : If a query needs to compare two timestamp with one timestamp provided in "YYYY-MM-DD" format, skipping the time part, it returns incorrect result.
Steps to reproduce :
1. Start a hive-cli.
2. Fire up the query -> select cast("2016-12-31 12:00:00" as timestamp) > "2016-12-30";
3. Expected result : true
4. Actual result : NULL
Detailed description :
If two primitives of different type needs to compared, a common comparator type is chosen. Prior to 2.1, Common type Text was chosen to compare Timestamp type and Text type.
In version 2.1, Common type Timestamp is chosen to compare Timestamp type and Text type. This leads to converting Text type (YYYY-MM-DD) into java.sql.Timestamp which throws exception saying the input is not in proper format. The exception is suppressed and a null is returned.
Code below from org.apache.hadoop.hive.ql.exec.FunctionRegistry
The bug was introduced in HIVE-13381