语法错误，“FLATTEN”处或附近出现意外符号

Posted 2023-04-18

【中文标题】语法错误，“FLATTEN”处或附近出现意外符号

【英文标题】：Syntax error, unexpected symbol at or near 'FLATTEN'

【发布时间】：2016-04-21 05:23:05

【问题描述】：

当我尝试这个时，它起作用了：

B = FOREACH A 
              X = STRSPLIT(agegroup,'-',0);

输出：

((20,30))
((20+))
((20,40))
and so on...

现在，我像这样尝试FLATTEN：

B = FOREACH A  
        X = FLATTEN(STRSPLIT(agegroup,'-',0));

我收到以下错误：

Pig Stack Trace
---------------
ERROR 1200: <file PigScript.pig, line 3, column 5>  Syntax error, unexpected symbol at or near 'FLATTEN'

org.apache.pig.impl.logicalLayer.FrontendException: ERROR 1000: Error during parsing. <file PigScript.pig, line 3, column 5>  Syntax error, unexpected symbol at or near 'FLATTEN'
            at org.apache.pig.PigServer$Graph.parseQuery(PigServer.java:1701)
            at org.apache.pig.PigServer$Graph.access$000(PigServer.java:1421)
            at org.apache.pig.PigServer.parseAndBuild(PigServer.java:354)
            at org.apache.pig.PigServer.executeBatch(PigServer.java:379)
            at org.apache.pig.PigServer.executeBatch(PigServer.java:365)
            at org.apache.pig.tools.grunt.GruntParser.executeBatch(GruntParser.java:140)
            at org.apache.pig.tools.grunt.GruntParser.processDump(GruntParser.java:769)
            at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:372)
            at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:198)
            at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:173)
            at org.apache.pig.tools.grunt.Grunt.exec(Grunt.java:84)
            at org.apache.pig.Main.run(Main.java:613)
            at org.apache.pig.Main.main(Main.java:158)
            at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
            at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
            at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
            at java.lang.reflect.Method.invoke(Method.java:606)
            at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
            at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
Caused by: Failed to parse: <file PigScript.pig, line 3, column 5>  Syntax error, unexpected symbol at or near 'FLATTEN'
            at org.apache.pig.parser.QueryParserDriver.parse(QueryParserDriver.java:241)
            at org.apache.pig.parser.QueryParserDriver.parse(QueryParserDriver.java:179)
            at org.apache.pig.PigServer$Graph.parseQuery(PigServer.java:1688)
            ... 18 more
================================================================================

请告诉我哪里弄错了。

【参考方案1】：

您不能在嵌套的 FOREACH 块中使用 FLATTEN。在嵌套的 FOREACH 块中只允许使用 CROSS、DISTINCT、FILTER、FOREACH、LIMIT 和 ORDER BY。

改变

B = FOREACH A  
                  X = FLATTEN(STRSPLIT(agegroup,'-',0));
              

到

B = FOREACH A GENERATE FLATTEN(STRSPLIT(agegroup,'-',0));

【讨论】：

任何参考文件指定这个？请发帖。