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https://issues.apache.org/jira/browse/TAJO-1415?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14491850#comment-14491850
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ASF GitHub Bot commented on TAJO-1415:
--------------------------------------
Github user sirpkt commented on a diff in the pull request:
https://github.com/apache/tajo/pull/454#discussion_r28211475
--- Diff: tajo-plan/src/main/java/org/apache/tajo/plan/ExprAnnotator.java
---
@@ -678,8 +679,26 @@ public EvalNode visitGeneralSetFunction(Context ctx,
Stack<Expr> stack, GeneralS
}
}
+
public static final Set<String> WINDOW_FUNCTIONS =
- Sets.newHashSet("row_number", "rank", "dense_rank", "percent_rank",
"cume_dist", "first_value", "lag");
+ Sets.newHashSet("row_number", "rank", "dense_rank", "percent_rank",
"cume_dist", "ntile", "first_value", "last_value", "lag");
+
+ public static final Set<String> NONFRAMABLE_WINDOW_FUNCTIONS =
+ Sets.newHashSet("row_number", "rank", "dense_rank", "percent_rank",
"cume_dist", "ntile", "lag", "lead");
+ public static final Set<String> FRAMABLE_WINDOW_FUNCTIONS =
+ Sets.newHashSet("first_value", "last_value", "nth_value");
+
+ public static FunctionType getFunctionType(String functionName, boolean
distinct) {
+// if
(NONFRAMABLE_WINDOW_FUNCTIONS.contains(functionName.toLowerCase()) ||
FRAMABLE_WINDOW_FUNCTIONS.contains(functionName.toLowerCase())) {
+ if (WINDOW_FUNCTIONS.contains(functionName.toLowerCase())) {
+ if (distinct && functionName.equalsIgnoreCase("row_number")) {
+ throw new NoSuchFunctionException("row_number() does not support
distinct keyword.");
--- End diff --
I just made a function wrapper for the code and did not change the code
itself,
however, I think ```distinct``` should be allowed with ```row_number()```
as we can use ```distinct row_number()``` in other DBMSs.
I'll check further about that.
> Window frame support
> --------------------
>
> Key: TAJO-1415
> URL: https://issues.apache.org/jira/browse/TAJO-1415
> Project: Tajo
> Issue Type: Sub-task
> Components: distributed query plan, parser, physical operator,
> planner/optimizer
> Reporter: Keuntae Park
> Assignee: Keuntae Park
> Fix For: window function
>
>
> We can define frame clause in window definition like
> {code}
> [ RANGE | ROWS ] frame_start
> [ RANGE | ROWS ] BETWEEN frame_start AND frame_end
> {code}
> , where frame_start and frame_end can be one of
> {code}
> UNBOUNDED PRECEDING
> value PRECEDING
> CURRENT ROW
> value FOLLOWING
> UNBOUNDED FOLLOWING
> {code}
> According to the window functions description of
> PostgreSQL(http://www.postgresql.org/docs/9.4/static/functions-window.html),
> there are two types of window functions based on window frame support.
> 1) row_number, rank, dense_rank, percent_rank, cume_dist, tile, lag and lead:
> these functions only work within window partition, which means window frame
> has no effect on these functions.
> 2) first_value, last_value, nth_value, and aggregation function as as window
> function: these functions should work with rows within window frame.
> Currently, Tajo parser recognize the window frame grammar but windowAggExec
> does not use that information.
> It works as if window frame is set as "RANGE BETWEEN UNBOUND PROCEEDING AND
> UNBOUNDED FOLLOWING", which is different from the default window frame
> setting of most DBMSs "RANGE BETWEEN UNBOUND PROCEEDING AND CURRENT ROW".
> Following should be done:
> 1) Applying correct default window frame for first_value, last_value,
> nth_value, and aggregation functions .
> 2) Supporting various window frame expressions.
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