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https://issues.apache.org/jira/browse/HIVE-15820?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17254363#comment-17254363
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Robbie Zhang commented on HIVE-15820:
-------------------------------------
HIVE-16935 introduces HiveStringUtils.removeComments() into Commands.java but
this issue still exists. There are two problems:
# Beeline.isComment() doesn't work properly on multiple lines. If the first
line starts with '–' or ‘#’, the rest lines are considered as comments so they
won't be passed to Commands.execute() at all.
# HiveStringUtils.removeComments(String, int[]) is used for a single line. It
checks if this line starts with '--' or '#'. If it is, an empty string is
returned immediately. In fact, for multiple lines, we should use
HiveStringUtils.removeComments(String).
I'll provide a patch later.
> comment at the head of beeline -e
> ---------------------------------
>
> Key: HIVE-15820
> URL: https://issues.apache.org/jira/browse/HIVE-15820
> Project: Hive
> Issue Type: Bug
> Components: Beeline
> Affects Versions: 1.2.1, 2.1.1
> Reporter: muxin
> Assignee: muxin
> Priority: Major
> Labels: patch
> Attachments: HIVE-15820.patch
>
>
> $ beeline -u jdbc:hive2://localhost:10000 -n test -e "
> > --asdfasdfasdfasdf
> > select * from test_table;
> > "
> expected result of the above command should be all rows of test_table(same as
> run in beeline interactive mode),but it does not output anything.
> the cause is that -e option will read commands as one string, and in method
> dispatch(String line) it calls function isComment(String line) in the first,
> which using
> 'lineTrimmed.startsWith("#") || lineTrimmed.startsWith("--")'
> to regard commands as a comment.
> two ways can be considered to fix this problem:
> 1. in method initArgs(String[] args), split command by '\n' into command list
> before dispatch when cl.getOptionValues('e') != null
> 2. in method dispatch(String line), remove comments using this:
> static String removeComments(String line) {
> if (line == null || line.isEmpty()) {
> return line;
> }
> StringBuilder builder = new StringBuilder();
> int escape = -1;
> for (int index = 0; index < line.length(); index++) {
> if (index < line.length() - 1 && line.charAt(index) ==
> line.charAt(index + 1)) {
> if (escape == -1 && line.charAt(index) == '-') {
> //find \n as the end of comment
> index = line.indexOf('\n',index+1);
> //there is no sql after this comment,so just break out
> if (-1==index){
> break;
> }
> }
> }
> char letter = line.charAt(index);
> if (letter == escape) {
> escape = -1; // Turn escape off.
> } else if (escape == -1 && (letter == '\'' || letter == '"')) {
> escape = letter; // Turn escape on.
> }
> builder.append(letter);
> }
> return builder.toString();
> }
> the second way can be a general solution to remove all comments start with
> '--' in a sql
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