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https://issues.apache.org/jira/browse/FLINK-15553?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17014077#comment-17014077
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Jark Wu commented on FLINK-15553:
---------------------------------
cc [~danny0405]
> Create table ddl support comment after computed column
> -------------------------------------------------------
>
> Key: FLINK-15553
> URL: https://issues.apache.org/jira/browse/FLINK-15553
> Project: Flink
> Issue Type: Improvement
> Components: Table SQL / API
> Affects Versions: 1.10.0
> Reporter: hailong wang
> Priority: Major
> Fix For: 1.11.0
>
>
> For now, we can define computed column in create table ddl, but we can not
> add comment after it just like regular table column, So we should support it,
> it's grammar as follows:
> {code:java}
> col_name AS expr [COMMENT 'string']
> {code}
> My idea is, we can introduce class
> {code:java}
> SqlTableComputedColumn{code}
> to wrap name, expression and comment, And just get the element from it will
> be ok.
> As for parserImpls.ftl, it can be like as follows:
> {code:java}
> identifier = SimpleIdentifier()
> <AS>
> expr = Expression(ExprContext.ACCEPT_NON_QUERY)
> [ <COMMENT> <QUOTED_STRING> {
> String p = SqlParserUtil.parseString(token.image);
> comment = SqlLiteral.createCharString(p, getPos());
> }]
> {
> SqlTableComputedColumn tableComputedColumn =
> new SqlTableComputedColumn(identifier, expr, comment, getPos());
> context.columnList.add(tableComputedColumn);
> }{code}
>
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