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Date: Fri, 30 Sep 2016 04:07:52 +0000
From: "Youwei Wang (Code Review)" <gerrit@cloudera.org>
To: Youwei Wang <youwei.a.wang@intel.com>, impala-cr@cloudera.com,
        reviews@impala.incubator.apache.org
CC: Jim Apple <jbapple@cloudera.com>, Mostafa Mokhtar <mmokhtar@cloudera.com>,
        Alex Behm <alex.behm@cloudera.com>
Reply-To: youwei.a.wang@intel.com
Subject: =?UTF-8?Q?=5BImpala-ASF-CR=5D_IMPALA-889=3A_Add_support_for_an_ISO-SQL_compliant_trim=28=29_function=2E=0A?=
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archived-at: Fri, 30 Sep 2016 04:08:00 -0000

Youwei Wang has uploaded a new patch set (#4).

Change subject: IMPALA-889: Add support for an ISO-SQL compliant trim() function.
......................................................................

IMPALA-889: Add support for an ISO-SQL compliant trim() function.

Purpose: Removes all instances of one or more characters from the
  specified direction(s) of a STRING value.
Syntax #1 TRIM(where FROM string_to_be_trimmed);
Syntax #2 TRIM(trim_char_set FROM string_to_be_trimmed);
Syntax #3 TRIM(where trim_char_set FROM string_to_be_trimmed);
Syntax #3 confirms the standard SQL syntax (Core SQL feature ID
  E021-09).

"where": Case-insensitive trim direction. Valid options are:
  leading|trailing|both. leading means trimming characters from the
  start; trailing means trimming characters from the end; both means
  trimming characters from both sides. These options should be
  provided without single/double quotation marks since they are not
  string literals but identifiers. NULL or empty argument implies
  "both" option. If an invalid option is specified, returns target
  untouched.
"trim_char_set": Case-sensitive characters to be removed. This
  argument is regarded as a character set going to be removed. So the
  occurrence order of each character doesn't matter and duplicated
  instance of same character will be ignored. NULL argument implies
  " "(space) by default. Empty argument return string_to_be_trimmed
  untouched.
"target": Case-sensitive target string to trim. This argument can be
  NULL. Blank argument causes parsing error.
Note: For Syntax #1, since no "characters" is specified, it trims
" "(space) by default. For Syntax #2, since no "where" is specified,
the option both is implied by default.
Return type: string

Examples:
Syntax #1:
trim(both 'abfg%' from 'abc%%defg%%%%%'); returns 'c%%de';
trim(leading FROM ' 123 '); returns '123 ';
trim(trailing FROM ' 123 '); returns ' 123';
Syntax #2:
trim('&@' FROM '&@&@&@&127+1-@&@&@&@')"; returns "127+1-";
Syntax #3:
trim(leading 'ab%' from 'abc%%defg%%%%%'); returns 'c%%defg%%%%%';
trim(trailing 'bfg%' from 'abc%%defg%%%%%'); returns 'abc%%de';
trim(both 'abfg%' from 'abc%%defg%%%%%')"; returns "c%%de";

Change-Id: I4753c608b0b00569bf8c5e95b132df6df358e602
---
M be/src/exprs/expr-test.cc
M be/src/exprs/string-functions-ir.cc
M be/src/exprs/string-functions.h
M common/function-registry/impala_functions.py
A common/function-registry/string-functions-ir.cc
M common/thrift/Exprs.thrift
M fe/src/main/cup/sql-parser.cup
A fe/src/main/java/com/cloudera/impala/analysis/TrimExpr.java
M fe/src/main/jflex/sql-scanner.flex
M fe/src/test/java/com/cloudera/impala/analysis/AnalyzeExprsTest.java
10 files changed, 1,439 insertions(+), 30 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/74/4474/4
-- 
To view, visit http://gerrit.cloudera.org:8080/4474
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I4753c608b0b00569bf8c5e95b132df6df358e602
Gerrit-PatchSet: 4
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Youwei Wang <youwei.a.wang@intel.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Jim Apple <jbapple@cloudera.com>
Gerrit-Reviewer: Mostafa Mokhtar <mmokhtar@cloudera.com>
Gerrit-Reviewer: Youwei Wang <youwei.a.wang@intel.com>