Repository: incubator-impala Updated Branches: refs/heads/master f15589573 -> 45e2329c9
IMPALA-4730: [DOCS] DISTINCT is allowed with group_concat() Remove the "DISTINCT not allowed" restriction. Add DISTINCT to syntax. Add an example showing usage of DISTINCT. Change-Id: Ib7d4555a5bc4c4195fa1529d1c1bdf39f98e7346 Reviewed-on: http://gerrit.cloudera.org:8080/7016 Reviewed-by: Alex Behm <[email protected]> Tested-by: Impala Public Jenkins Project: http://git-wip-us.apache.org/repos/asf/incubator-impala/repo Commit: http://git-wip-us.apache.org/repos/asf/incubator-impala/commit/45e2329c Tree: http://git-wip-us.apache.org/repos/asf/incubator-impala/tree/45e2329c Diff: http://git-wip-us.apache.org/repos/asf/incubator-impala/diff/45e2329c Branch: refs/heads/master Commit: 45e2329c92c2e3e31c6940e52bedfa20f48c8fd7 Parents: f155895 Author: John Russell <[email protected]> Authored: Tue May 30 11:33:43 2017 -0700 Committer: Impala Public Jenkins <[email protected]> Committed: Tue May 30 19:01:20 2017 +0000 ---------------------------------------------------------------------- docs/topics/impala_group_concat.xml | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/incubator-impala/blob/45e2329c/docs/topics/impala_group_concat.xml ---------------------------------------------------------------------- diff --git a/docs/topics/impala_group_concat.xml b/docs/topics/impala_group_concat.xml index ffa4084..476d7dc 100644 --- a/docs/topics/impala_group_concat.xml +++ b/docs/topics/impala_group_concat.xml @@ -45,9 +45,7 @@ under the License. <p conref="../shared/impala_common.xml#common/syntax_blurb"/> -<!-- Might allow DISTINCT at some point. Check: does it allow ALL now? --> - -<codeblock>GROUP_CONCAT([ALL] <varname>expression</varname> [, <varname>separator</varname>])</codeblock> +<codeblock>GROUP_CONCAT([ALL<ph rev="IMPALA-4730"> | DISTINCT</ph>] <varname>expression</varname> [, <varname>separator</varname>])</codeblock> <p conref="../shared/impala_common.xml#common/concat_blurb"/> @@ -61,12 +59,6 @@ under the License. <b>Return type:</b> <codeph>STRING</codeph> </p> - <p conref="../shared/impala_common.xml#common/restrictions_blurb"/> - - <p> - You cannot apply the <codeph>DISTINCT</codeph> operator to the argument of this function. - </p> - <p conref="../shared/impala_common.xml#common/analytic_not_allowed_caveat"/> <p> @@ -100,6 +92,20 @@ under the License. +---------------------------------+ </codeblock> + <p rev="IMPALA-4730"> + Specify the <codeph>DISTINCT</codeph> keyword to eliminate duplicate values from + the concatenated result: + </p> + +<codeblock rev="IMPALA-4730"> +[localhost:21000] > select group_concat(distinct s) from t1; ++--------------------------+ +| group_concat(distinct s) | ++--------------------------+ +| three, two, one | ++--------------------------+ +</codeblock> + <p> The optional separator lets you format the result in flexible ways. The separator can be an arbitrary string expression, not just a single character.
