Mihaly Szjatinya has uploaded a new patch set (#17). (
http://gerrit.cloudera.org:8080/21825 )
Change subject: IMPALA-889: Add trim() function matching ANSI SQL definition
......................................................................
IMPALA-889: Add trim() function matching ANSI SQL definition
As agreed in JIRA discussions, the current PR extends existing TRIM
functionality with the support of SQL-standardized TRIM-FROM syntax:
TRIM({[LEADING / TRAILING / BOTH] | [STRING characters]} FROM expr).
Implemented based on the existing LTRIM / RTRIM / BTRIM family of
functions prepared earlier in IMPALA-6059 and extended for UTF-8 in
IMPALA-12718. Besides, partly based on abandoned PR
https://gerrit.cloudera.org/#/c/4474 and similar EXTRACT-FROM
functionality from https://github.com/apache/impala/commit/543fa73f3a846
f0e4527514c993cb0985912b06c.
Supported syntaxes:
Syntax #1 TRIM(<where> FROM <string>);
Syntax #2 TRIM(<charset> FROM <string>);
Syntax #3 TRIM(<where> <charset> FROM <string>);
"where": Case-insensitive trim direction. Valid options are "leading",
"trailing", and "both". "leading" means trimming characters from the
start; "trailing" means trimming characters from the end; "both" means
trimming characters from both sides. For Syntax #2, since no "where"
is specified, the option "both" is implied by default.
"charset": Case-sensitive characters to be removed. This argument is
regarded as a character set going to be removed. The occurrence order
of each character doesn't matter and duplicated instances of the same
character will be ignored. NULL argument implies " " (standard space)
by default. Empty argument ("" or '') makes TRIM return the string
untouched. For Syntax #1, since no "charset" is specified, it trims
" " (standard space) by default.
"string": Case-sensitive target string to trim. This argument can be
NULL.
The UTF8_MODE query option is honored by TRIM-FROM, similarly to
existing TRIM().
UTF8_TRIM-FROM can be used to force UTF8 mode regardless of the query
option.
Design Notes:
1. No-BE. Since the existing LTRIM / RTRIM / BTRIM functions fully cover
all needed use-cases, no backend logic is required. This differs from
similar EXTRACT-FROM.
2. Syntax wrapper. TrimFromExpr class was introduced as a syntax
wrapper around FunctionCallExpr, which instantiates one of the regular
LTRIM / RTRIM / BTRIM functions. TrimFromExpr's role is to maintain
the integrity of the "phantom" TRIM-FROM built-in function.
3. No TRIM keyword. Following EXTRACT-FROM, no "TRIM" keyword was
added to the language. Although generally a keyword would allow easier
and better parsing, on the negative side it restricts token's usage in
general context. However, leading/trailing/both, being previously
saved as reserved words, are now added as keywords to make possible
their usage with no escaping.
Change-Id: I3c4fa6d0d8d0684c4b6d8dac8fd531d205e4f7b4
---
M be/src/exprs/expr-test.cc
M docs/topics/impala_string_functions.xml
M fe/src/main/cup/sql-parser.cup
A fe/src/main/java/org/apache/impala/analysis/TrimFromExpr.java
M fe/src/main/jflex/sql-scanner.flex
M fe/src/test/java/org/apache/impala/analysis/AnalyzeExprsTest.java
M fe/src/test/java/org/apache/impala/analysis/ToSqlTest.java
M
testdata/workloads/functional-query/queries/QueryTest/utf8-string-functions.test
8 files changed, 565 insertions(+), 9 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/25/21825/17
--
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I3c4fa6d0d8d0684c4b6d8dac8fd531d205e4f7b4
Gerrit-Change-Number: 21825
Gerrit-PatchSet: 17
Gerrit-Owner: Mihaly Szjatinya <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Daniel Becker <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Michael Smith <[email protected]>
Gerrit-Reviewer: Mihaly Szjatinya <[email protected]>
Gerrit-Reviewer: Noemi Pap-Takacs <[email protected]>
Gerrit-Reviewer: Peter Rozsa <[email protected]>
