It will be more appropriate if I add my file to have data to facilitate quick
test.
[root@maprdemo clicks]# cat sthota_test_1.json
{"a":"r1cl1", "b":"r1c2","c":{ "x" : 1, "y" : "a string", "z" : [ 1] }}
{"a":"r2cl1", "b":"r2c2","c":{ "x" : 2, "y" : "a string", "z" : [ 1,2] }}
{"a":"r3cl1", "b":"r3c2","c":{ "x" : 3, "y" : "a string", "z" : [ 1,2,3] }}
{"a":"r4cl1", "b":"r4c2","c":{ "x" : 4, "y" : "a string", "z" : [ 1,2,3,4] }}
{"a":"r5cl1", "b":"r5c2","c":{ "x" : 5, "y" : "a string", "z" : [ 1,2,3,4,5] }}
{"a":"r6cl1", "b":"r6c2","c":{ "x" : 6, "y" : "a string" }}
Begin forwarded message:
> From: Sudhakar Thota <[email protected]>
> Subject: Drill - Flatten function - help please
> Date: February 3, 2015 at 11:52:39 AM PST
> To: [email protected]
>
> Hi Drillers,
>
> I have a request here about flatten function. I want to know if this is an
> expected behavior of drill flatten function with json documents.
>
> Listing-1 is contents of my json collection where I have intentionally
> included a empty array.
> Listing-2 shows that if I don’t call flatten function it shows all records.
> Listing-3 shows that if I call flatten function, row6 (r6cl1…) is ignored. I
> am using that in my projections not in predicate, but it looks like treated
> as predicate.
>
> Please correct me if I am wrong and let me know if there is any work around.
>
> Listing:1
>
> 0: jdbc:drill:> SELECT t.a,t.b,t.c.x, t.c.y, t.c.z from
> dfs.`/data/nested/clicks/sthota_test_1.json` as t;
> +------------+------------+------------+------------+------------+
> | a | b | EXPR$2 | EXPR$3 | EXPR$4 |
> +------------+------------+------------+------------+------------+
> | r1cl1 | r1c2 | 1 | a string | ["1"] |
> | r2cl1 | r2c2 | 2 | a string | ["1","2"] |
> | r3cl1 | r3c2 | 3 | a string | ["1","2","3"] |
> | r4cl1 | r4c2 | 4 | a string | ["1","2","3","4"] |
> | r5cl1 | r5c2 | 5 | a string | ["1","2","3","4","5"] |
> | r6cl1 | r6c2 | 6 | a string | [] |
> +------------+------------+------------+------------+------------+
> 6 rows selected (0.125 seconds)
> 0: jdbc:drill:>
>
> Listing:2
>
> 0: jdbc:drill:> SELECT t.a,t.b,t.c.x, t.c.y from
> dfs.`/data/nested/clicks/sthota_test_1.json` as t;
> +------------+------------+------------+------------+
> | a | b | EXPR$2 | EXPR$3 |
> +------------+------------+------------+------------+
> | r1cl1 | r1c2 | 1 | a string |
> | r2cl1 | r2c2 | 2 | a string |
> | r3cl1 | r3c2 | 3 | a string |
> | r4cl1 | r4c2 | 4 | a string |
> | r5cl1 | r5c2 | 5 | a string |
> | r6cl1 | r6c2 | 6 | a string |
> +------------+------------+------------+------------+
> 6 rows selected (0.163 seconds)
>
> Listing:3
>
> 0: jdbc:drill:> SELECT t.a,t.b,t.c.x, t.c.y, flatten(t.c.z) from
> dfs.`/data/nested/clicks/sthota_test_1.json` as t;
> +------------+------------+------------+------------+------------+
> | a | b | EXPR$2 | EXPR$3 | EXPR$4 |
> +------------+------------+------------+------------+------------+
> | r1cl1 | r1c2 | 1 | a string | 1 |
> | r2cl1 | r2c2 | 2 | a string | 1 |
> | r2cl1 | r2c2 | 2 | a string | 2 |
> | r3cl1 | r3c2 | 3 | a string | 1 |
> | r3cl1 | r3c2 | 3 | a string | 2 |
> | r3cl1 | r3c2 | 3 | a string | 3 |
> | r4cl1 | r4c2 | 4 | a string | 1 |
> | r4cl1 | r4c2 | 4 | a string | 2 |
> | r4cl1 | r4c2 | 4 | a string | 3 |
> | r4cl1 | r4c2 | 4 | a string | 4 |
> | r5cl1 | r5c2 | 5 | a string | 1 |
> | r5cl1 | r5c2 | 5 | a string | 2 |
> | r5cl1 | r5c2 | 5 | a string | 3 |
> | r5cl1 | r5c2 | 5 | a string | 4 |
> | r5cl1 | r5c2 | 5 | a string | 5 |
> +------------+------------+------------+------------+------------+
> 15 rows selected (0.171 seconds)
>
> Thanks
> Sudhakar Thota
>
