left('abcdef', 1) ===> a
left('abcdef', 2) ===> ab
right('abcdef', 1) ===> f
right('abcdef', 2) ===> ef
Don't accept this patch. Here is two problems.
1. it is the same problem with substr, Parsing error
2. when give function name to (left, right), it failed with parse.
(I might think it is because of reserved keyword(left join or right join).
so. I changed function name left -> from_left, right -> from_right.
If the second parameter (i.e., size) is null, the result should be null. Others look great for me.
I'll submit a new patch that resolved reserved words.
I've attached the updated patch. This patch does as follows:
If there are no objection, I'll commit it after a while.
The latest patch doesn't look like to contain the difference between the master branch and this issue.
Also, there are some commented out codes.
I submitted the wrong file. I updated the third patch.
The commented out lines should be enabled after auto casting is implemented.
+1 for the patch.
committed it to master. Thank you for your contribution!
SUCCESS: Integrated in Tajo-trunk-postcommit #581 (See https://builds.apache.org/job/Tajo-trunk-postcommit/581/)
TAJO-352: Implement right/left(text, size) function. (DaeMyung Kang via hyunsik) (hyunsik: https://git-wip-us.apache.org/repos/asf?p=incubator-tajo.git&a=commit&h=43ec04aaa34ffe5c5da2cfd05ff919ffac44044b)