运行 SQL 查询时出现 PySpark 错误

Question

由于我缺乏在 pyspark / python 中编写代码的知识，我决定在 spark.sql 中编写查询。我用两种格式编写了查询。第一种格式允许 EOL 中断。但是，在那种格式下我得到一个错误，见下文：

 results5 = spark.sql("SELECT\
  appl_stock.Open\
 ,appl_stock.Close\
FROM appl_stock\
WHERE appl_stock.Close < 500")

上述格式会产生以下错误：

 ---------------------------------------------------------------------------
Py4JJavaError                             Traceback (most recent call last)
~/spark-2.1.0-bin-hadoop2.7/python/pyspark/sql/utils.py in deco(*a, **kw)
     62         try:
---> 63             return f(*a, **kw)
     64         except py4j.protocol.Py4JJavaError as e:

~/spark-2.1.0-bin-hadoop2.7/python/lib/py4j-0.10.4-src.zip/py4j/protocol.py in get_return_value(answer, gateway_client, target_id, name)
    318                     "An error occurred while calling {0}{1}{2}.\n".
--> 319                     format(target_id, ".", name), value)
    320             else:

Py4JJavaError: An error occurred while calling o19.sql.
: org.apache.spark.sql.catalyst.parser.ParseException:
mismatched input '.' expecting {<EOF>, ',', 'FROM', 'WHERE', 'GROUP', 'ORDER', 'HAVING', 'LIMIT', 'LATERAL', 'WINDOW', 'UNION', 'EXCEPT', 'MINUS', 'INTERSECT', 'SORT', 'CLUSTER', 'DISTRIBUTE'}(line 1, pos 35)

== SQL ==
SELECT  appl_stock.Open  appl_stock.CloseFROM appl_stockWHERE appl_stock.Close < 500
-----------------------------------^^^

    at org.apache.spark.sql.catalyst.parser.ParseException.withCommand(ParseDriver.scala:197)
    at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parse(ParseDriver.scala:99)
    at org.apache.spark.sql.execution.SparkSqlParser.parse(SparkSqlParser.scala:45)
    at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parsePlan(ParseDriver.scala:53)
    at org.apache.spark.sql.SparkSession.sql(SparkSession.scala:592)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
    at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
    at py4j.Gateway.invoke(Gateway.java:280)
    at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
    at py4j.commands.CallCommand.execute(CallCommand.java:79)
    at py4j.GatewayConnection.run(GatewayConnection.java:214)
    at java.lang.Thread.run(Thread.java:748)

During handling of the above exception, another exception occurred:

ParseException                            Traceback (most recent call last)
<ipython-input-38-4920f7e68c0e> in <module>()
----> 1 results5 = spark.sql("SELECT  appl_stock.Open  appl_stock.CloseFROM appl_stockWHERE appl_stock.Close < 500")

~/spark-2.1.0-bin-hadoop2.7/python/pyspark/sql/session.py in sql(self, sqlQuery)
    539         [Row(f1=1, f2=u'row1'), Row(f1=2, f2=u'row2'), Row(f1=3, f2=u'row3')]
    540         """
--> 541         return DataFrame(self._jsparkSession.sql(sqlQuery), self._wrapped)
    542
    543     @since(2.0)

~/spark-2.1.0-bin-hadoop2.7/python/lib/py4j-0.10.4-src.zip/py4j/java_gateway.py in __call__(self, *args)
   1131         answer = self.gateway_client.send_command(command)
   1132         return_value = get_return_value(
-> 1133             answer, self.gateway_client, self.target_id, self.name)
   1134
   1135         for temp_arg in temp_args:

~/spark-2.1.0-bin-hadoop2.7/python/pyspark/sql/utils.py in deco(*a, **kw)
     71                 raise AnalysisException(s.split(': ', 1)[1], stackTrace)
     72             if s.startswith('org.apache.spark.sql.catalyst.parser.ParseException: '):
---> 73                 raise ParseException(s.split(': ', 1)[1], stackTrace)
     74             if s.startswith('org.apache.spark.sql.streaming.StreamingQueryException: '):
     75                 raise StreamingQueryException(s.split(': ', 1)[1], stackTrace)

ParseException: "\nmismatched input '.' expecting {<EOF>, ',', 'FROM', 'WHERE', 'GROUP', 'ORDER', 'HAVING', 'LIMIT', 'LATERAL', 'WINDOW', 'UNION', 'EXCEPT', 'MINUS', 'INTERSECT', 'SORT', 'CLUSTER', 'DISTRIBUTE'}(line 1, pos 35)\n\n== SQL ==\nSELECT  appl_stock.Open  appl_stock.CloseFROM appl_stockWHERE appl_stock.Close < 500\n-----------------------------------^^^\n"

而以下代码产生了成功的结果，请参见下文：

 results6 = spark.sql("SELECT appl_stock.Open ,appl_stock.Close FROM appl_stock WHERE appl_stock.Close < 500")

有人可以让我知道为什么第一个代码不起作用，但第二个代码可以吗？

干杯

原文由 barlow1 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

因为您在第一个中使用 \ 并且它作为奇怪的语法传递给 spark。如果要编写多行 SQL 语句，请使用三重引号：

 results5 = spark.sql("""SELECT
  appl_stock.Open
 ,appl_stock.Close
FROM appl_stock
WHERE appl_stock.Close < 500""")

原文由 Scratch‘N’Purr 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 2

奇怪的是，如果我用 ; 终止我的 SQL 语句，就会为我抛出这个问题。只需删除即可修复它。

IE

 spark.sql("""
SELECT * FROM foo WHERE bar = 3;
""")

休息。

 spark.sql("""
SELECT * FROM foo WHERE bar = 3
""")

才不是。

原文由 ijoseph 发布，翻译遵循 CC BY-SA 4.0 许可协议