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https://issues.apache.org/jira/browse/TRAFODION-2973?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16380680#comment-16380680
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ASF GitHub Bot commented on TRAFODION-2973:
-------------------------------------------
Github user DaveBirdsall commented on a diff in the pull request:
https://github.com/apache/trafodion/pull/1458#discussion_r171317972
--- Diff: docs/sql_reference/src/asciidoc/_chapters/sql_statements.adoc ---
@@ -6989,20 +6989,22 @@ By abstracting the complicated parts of the query
into simpler, separate and log
+
specifies the unique name of the CTE to be created, which is a valid SQL
identifier with a maximum of 128 characters. Duplicate names are not allowed in
a single with-clause.
-* `"[" ANY _N_ "]" | "[" FIRST _N_ "]"`
+* `"[" ANY _N_ "]" | "[" FIRST _N_ "]" | "[" LAST _N_ "]" `
+
specifies that _N_ rows are to be returned (assuming the table has at
least _N_ rows and that the qualification
criteria specified in the WHERE clause, if any, would select at least _N_
rows) and you do not care which _N_ rows
are chosen (out of the qualified rows) to actually be returned.
+
-_You must enclose ANY N or FIRST N in square brackets ([])._ The quotation
marks ("") around each square bracket in
+You must enclose `ANY _N_`, `FIRST _N_` or `LAST _N_` in square brackets
([]). The quotation marks ("") around each square bracket in
the syntax diagram indicate that the bracket is a required character that
you must type as shown (for example, [ANY 10]
or [FIRST 5]). Do not include quotation marks in ANY or FIRST clauses.
+
[FIRST _N_] is different from [ANY _N_] only if you use ORDER BY on any of
the columns in the select list to sort the
result table of the SELECT statement. _N_ is an unsigned numeric literal
with no scale. If _N_ is greater than the number
of rows in the table, all rows are returned. [ANY _N_] and [FIRST _N_] are
disallowed in nested SELECT statements and on
either side of a UNION operation.
++
+`[LAST _N_]` performs a full table scan and calculates elapsed time. The
_N_ must be 0 or 1. `[LAST _0_]` does not return any rows. `[LAST _1_]` returns
only the last qualified row.
--- End diff --
"... performs a full table scan ..." This is not quite correct. Our query
plan might have key predicates that limit us to less than a full table scan,
for example. A more accurate description might be "... performs the entire
query ...".
> Add syntax and examples of *[LAST N] (SELECT Statement)* in *Trafodion SQL
> Reference Manual*
> ---------------------------------------------------------------------------------------------
>
> Key: TRAFODION-2973
> URL: https://issues.apache.org/jira/browse/TRAFODION-2973
> Project: Apache Trafodion
> Issue Type: Documentation
> Reporter: Liu Yu
> Assignee: Liu Yu
> Priority: Major
>
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