1. Create a toy table using the HBase shell with these HBase shell commands
create 'WiredMinds', 'customer', 'pi', 'visit'
put 'WiredMinds', 'row1', 'customer:a', 'c1'
put 'WiredMinds', 'row2', 'customer:a', 'c2'
put 'WiredMinds', 'row3', 'customer:a', 'c3'
put 'WiredMinds', 'row4', 'pi:a', 'p1'
put 'WiredMinds', 'row5', 'pi:a', 'p2'
put 'WiredMinds', 'row6', 'pi:a', 'p3'
put 'WiredMinds', 'row7', 'visit:a', 'p1'
put 'WiredMinds', 'row8', 'visit:a', 'p2'
put 'WiredMinds', 'row9', 'visit:a', 'p3'
put 'WiredMinds', 'row10', 'customer:a', 'xyz'
put 'WiredMinds', 'row10', 'pi:a', 'xyz'
put 'WiredMinds', 'row10', 'visit:a', 'xyz'
put 'WiredMinds', 'row11', 'visit:a', 'abc'
put 'WiredMinds', 'row11', 'pi:a', 'abc'
put 'WiredMinds', 'row11', 'customer:a', 'abc'

2. Create an external HBase table in Hive with:
create external table customer_journey
(rowkey string,
customer_a string,
pi_a string,
visit_a string)
stored by 'org.apache.hadoop.hive.hbase.HBaseStorageHandler'
with serdeproperties ("hbase.columns.mapping"=":key,customer:a,pi:a,visit:a")
tblproperties("hbase.table.name" = "WiredMinds");

3. Query the table in Impala and see the bug:
[localhost:21000] > select count(*) from customer_journey where customer_a is not null;
Query: select count(*) from customer_journey where customer_a is not null
+----------+
| count(*) |
+----------+
| 5        |
+----------+
Returned 1 row(s) in 0.42s
[localhost:21000] > select count(*) from customer_journey where pi_a = 'xyz';
Query: select count(*) from customer_journey where pi_a = 'xyz'
+----------+
| count(*) |
+----------+
| 1        |
+----------+
Returned 1 row(s) in 0.44s
[localhost:21000] > select count(*) from customer_journey where customer_a is not null and pi_a = 'xyz';
Query: select count(*) from customer_journey where customer_a is not null and pi_a = 'xyz'
+----------+
| count(*) |
+----------+
| 4        |
+----------+
Returned 1 row(s) in 0.42s