[PIG-3375] CASE does not preserve the order of when branches

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.12.0
• Assignee: Cheolsoo Park
• Reporter: Cheolsoo Park
• Created: 05/Jul/13 19:37
• Updated: 14/Oct/13 16:45
• Resolved: 09/Jul/13 19:17

Description

Currently CASE expression builds nested BinCond expressions in the following order: from top to bottom when branches => from in to out bin conds.

This can be confusing if non-mutually exclusive conditions are used in when branches. For example,

CASE 
    WHEN x > 100 THEN 'a'
    WHEN x > 50  THEN 'b'
    ELSE 'c'
END

is converted to

x > 50 ? 'b' : ( x > 100 ? 'a' : 'c' )

Now if x is 1000, the result is 'b', which is not quite expected.

Instead, we should construct nested BinCond expressions in the same order as that of when branches, i.e.

x > 100 ? 'a' : ( x > 50 ? 'b' : 'c' )