我正在从Apache Spark中查询Apache演练。我的问题是，如何从Spark发送除select * from之外的sql命令来进行钻取。默认情况下，spark在select * from中发送查询。另外，当我查询除dfs之外的其他架构时，我得到了NullPointerException。请帮忙！
我的Spark版本是2.2.0
这是我的代码： 1.模式= dfs：
dataframe_mysql = spark.read.format("jdbc").option("url", "jdbc:drill:zk=%s;schema=%s;" % (foreman,schema)).option("driver","org.apache.drill.jdbc.Driver").option("dbtable","\"/user/titanic_data/test.csv\"").load()
模式= MySQL
dataframe_mysql = spark.read.format("jdbc").option("url", "jdbc:drill:zk=%s;schema=MySQL;" % (foreman)).option("driver","org.apache.drill.jdbc.Driver").option("dbtable","MySQL.\"spark3\"").load()
这是完整的错误：
Name: org.apache.toree.interpreter.broker.BrokerException
Message: Py4JJavaError: An error occurred while calling o40.load.
: java.sql.SQLException: Failed to create prepared statement: SYSTEM ERROR: NullPointerException
[Error Id: d1e4b310-f4df-4e7c-90ae-983cc5c89f94 on inpunpclx1825e.kih.kmart.com:31010]
at org.apache.drill.jdbc.impl.DrillJdbc41Factory.newServerPreparedStatement(DrillJdbc41Factory.java:147)
at org.apache.drill.jdbc.impl.DrillJdbc41Factory.newPreparedStatement(DrillJdbc41Factory.java:108)
at org.apache.drill.jdbc.impl.DrillJdbc41Factory.newPreparedStatement(DrillJdbc41Factory.java:50)
at oadd.org.apache.calcite.avatica.AvaticaConnection.prepareStatement(AvaticaConnection.java:278)
at org.apache.drill.jdbc.impl.DrillConnectionImpl.prepareStatement(DrillConnectionImpl.java:389)
at oadd.org.apache.calcite.avatica.AvaticaConnection.prepareStatement(AvaticaConnection.java:119)
at org.apache.drill.jdbc.impl.DrillConnectionImpl.prepareStatement(DrillConnectionImpl.java:422)
at org.apache.spark.sql.execution.datasources.jdbc.JDBCRDD$.resolveTable(JDBCRDD.scala:60)
at org.apache.spark.sql.execution.datasources.jdbc.JDBCRelation.<init>(JDBCRelation.scala:113)
at org.apache.spark.sql.execution.datasources.jdbc.JdbcRelationProvider.createRelation(JdbcRelationProvider.scala:47)
at org.apache.spark.sql.execution.datasources.DataSource.resolveRelation(DataSource.scala:306)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:178)
at org.apache.spark.sql.DataFrameReader.load(DataFrameReader.scala:146)
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)
(<class 'py4j.protocol.Py4JJavaError'>, Py4JJavaError('An error occurred while calling o40.load.\n', JavaObject id=o41), <traceback object at 0x7f00106d6488>)
StackTrace: org.apache.toree.interpreter.broker.BrokerState$$anonfun$markFailure$1.apply(BrokerState.scala:163)
org.apache.toree.interpreter.broker.BrokerState$$anonfun$markFailure$1.apply(BrokerState.scala:163)
scala.Option.foreach(Option.scala:257)
org.apache.toree.interpreter.broker.BrokerState.markFailure(BrokerState.scala:162)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
py4j.Gateway.invoke(Gateway.java:280)
py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
py4j.commands.CallCommand.execute(CallCommand.java:79)
py4j.GatewayConnection.run(GatewayConnection.java:214)
java.lang.Thread.run(Thread.java:748)
我已将默认钻取报价从``更改为''，以便在spark和钻探之间不会出现任何报价标识符问题。