[DRILL-7396] Exception when trying to access last element of an array with repeated_count

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.16.0
• Component/s: Functions - Drill
• Assignee: Unassigned
• Reporter: benj
• Created: 04/Oct/19 09:11
• Updated: 04/Oct/19 09:11

Description

Use of array in drill is not friendly

SELECT (split('a,b,c',','))[0]; /*NOK */
Error: SYSTEM ERROR: ClassCastException: org.apache.drill.common.expression.FunctionCall cannot be cast to org.apache.drill.common.expression.SchemaPath

/* outer SELECT needed*/
SELECT x[0] FROM (SELECT split('a,b,c',',') x); /* OK */

And access last element of an array is worse

SELECT x[repeated_count(x) - 1] AS lasteltidx FROM (SELECT split('a,b,c',',') x);
Error: SYSTEM ERROR: ClassCastException: org.apache.calcite.rex.RexCall cannot be cast to org.apache.calcite.rex.RexLiteral

/* while */
SELECT x[2] lastelt, (repeated_count(x) - 1) AS lasteltidx FROM (SELECT split('a,b,c',',') x);
+---------+------------+
| lastelt | lasteltidx |
+---------+------------+
| c       | 2          |
+---------+------------+