In a table, column with null values we present as nulls or empty values with other columns. I never had an experience with c1, c2, c3 (columns ) not presented when c3 has null values even though c1, c2 have notnull values.
Sudhakar Thota Sent from my iPhone > On Feb 3, 2015, at 11:57 AM, Andries Engelbrecht <[email protected]> > wrote: > > In listing 3 it looks like flatten is doing the correct thing by representing > each element in the array with a new row and the element in the column output. > And also for arrays that are empty there is no output row. > > —Andries > >> On Feb 3, 2015, at 11:54 AM, Sudhakar Thota <[email protected]> wrote: >> >> 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 >
