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https://issues.apache.org/jira/browse/CALCITE-3300?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16948167#comment-16948167
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Wang Weidong edited comment on CALCITE-3300 at 10/10/19 3:31 AM:
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[~julianhyde] Will you reply my discussion ？
was (Author: wangweidong):
[~julianhyde] Will reply my discussion ？
> Add a star identifier as operand to "SqlCountAggFunction" if no operands
> given while in the method "createCall"
> ---------------------------------------------------------------------------------------------------------------
>
> Key: CALCITE-3300
> URL: https://issues.apache.org/jira/browse/CALCITE-3300
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.21.0
> Reporter: Wang Weidong
> Assignee: Wang Weidong
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> h4. Procedure to reproduce the problem:
> - create table {{~^t^~}}
> - parse query select count(*) from t to SqlNode
> - convert SqlNode to RelNode
> - convert RelNode to SqlNode
> - validate the result SqlNode
> test code is like this
> {code:java}
> // code placeholder
> @Test
> public void testSelectCountAll() throws Exception {
> try (Statement s = parserContext.getStatement()) {
> s.execute("create table if not exists t (i int not null)");
> String sql = "select count(*) from t";
> SqlNode sqlNode = parserContext.parseStmt(sql);
> parserContext.getSqlValidator().validate(sqlNode);
> RelNode relNode =
> parserContext.getSqlToRelConverter().convertQuery(sqlNode, true, true).rel;
> SqlNode sqlNodeNew = toSqlNode(relNode);
> parserContext.getSqlValidator().validate(sqlNodeNew);
> }
> }
> {code}
> Finally we will get an exception as follow:
> {code:java}
> // code placeholder
> org.apache.calcite.runtime.CalciteContextException: At line 0, column 0:
> Invalid number of arguments to function 'COUNT'. Was expecting 1
> argumentsorg.apache.calcite.runtime.CalciteContextException: At line 0,
> column 0: Invalid number of arguments to function 'COUNT'. Was expecting 1
> arguments at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
> Method) at
> sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
> at
> sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
> at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at
> org.apache.calcite.runtime.Resources$ExInstWithCause.ex(Resources.java:463)
> at org.apache.calcite.sql.SqlUtil.newContextException(SqlUtil.java:783) at
> org.apache.calcite.sql.SqlUtil.newContextException(SqlUtil.java:768) at
> org.apache.calcite.sql.validate.SqlValidatorImpl.newValidationError(SqlValidatorImpl.java:4753)
> at
> org.apache.calcite.sql.validate.SqlValidatorImpl.handleUnresolvedFunction(SqlValidatorImpl.java:1699)
> at org.apache.calcite.sql.SqlFunction.deriveType(SqlFunction.java:270) at
> org.apache.calcite.sql.SqlFunction.deriveType(SqlFunction.java:215) at
> org.apache.calcite.sql.fun.SqlCountAggFunction.deriveType(SqlCountAggFunction.java:83)
> at
> org.apache.calcite.sql.validate.SqlValidatorImpl$DeriveTypeVisitor.visit(SqlValidatorImpl.java:5477)
> at
> org.apache.calcite.sql.validate.SqlValidatorImpl$DeriveTypeVisitor.visit(SqlValidatorImpl.java:5464)
> at org.apache.calcite.sql.SqlCall.accept(SqlCall.java:138) at
> org.apache.calcite.sql.validate.SqlValidatorImpl.deriveTypeImpl(SqlValidatorImpl.java:1629)
> at
> org.apache.calcite.sql.validate.SqlValidatorImpl.deriveType(SqlValidatorImpl.java:1614)
> at
> org.apache.calcite.sql.validate.SqlValidatorImpl.expandSelectItem(SqlValidatorImpl.java:457)
> at
> org.apache.calcite.sql.validate.SqlValidatorImpl.validateSelectList(SqlValidatorImpl.java:4017)
> at
> org.apache.calcite.sql.validate.SqlValidatorImpl.validateSelect(SqlValidatorImpl.java:3280)
> at
> org.apache.calcite.sql.validate.SelectNamespace.validateImpl(SelectNamespace.java:60)
> at
> org.apache.calcite.sql.validate.AbstractNamespace.validate(AbstractNamespace.java:84)
> at
> org.apache.calcite.sql.validate.SqlValidatorImpl.validateNamespace(SqlValidatorImpl.java:967)
> at
> org.apache.calcite.sql.validate.SqlValidatorImpl.validateQuery(SqlValidatorImpl.java:943)
> at org.apache.calcite.sql.SqlSelect.validate(SqlSelect.java:225) at
> org.apache.calcite.sql.validate.SqlValidatorImpl.validateScopedExpression(SqlValidatorImpl.java:918)
> at
> org.apache.calcite.sql.validate.SqlValidatorImpl.validate(SqlValidatorImpl.java:628)
> at
> org.apache.calcite.test.OptimizeTest.testSelectCountAll(OptimizeTest.java:220)
> 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
> org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
> at
> org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
> at
> org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
> at
> org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
> at
> org.junit.rules.ExpectedException$ExpectedExceptionStatement.evaluate(ExpectedException.java:239)
> at org.junit.rules.RunRules.evaluate(RunRules.java:20) at
> org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at
> org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
> at
> org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
> at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at
> org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at
> org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at
> org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at
> org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at
> org.junit.runners.ParentRunner.run(ParentRunner.java:363) at
> org.junit.runner.JUnitCore.run(JUnitCore.java:137) at
> com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
> at
> com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
> at
> com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
> at
> com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)Caused
> by: org.apache.calcite.sql.validate.SqlValidatorException: Invalid number of
> arguments to function 'COUNT'. Was expecting 1 arguments at
> sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at
> sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
> at
> sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
> at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at
> org.apache.calcite.runtime.Resources$ExInstWithCause.ex(Resources.java:463)
> at org.apache.calcite.runtime.Resources$ExInst.ex(Resources.java:572) ... 47
> more{code}
>
> After debugging, I found that the *main causes* of this exception are as
> follows.
> First, while converting RelNode to SqlNode, in the method
> {{~^org.apache.calcite.rel.rel2sql.SqlImplementor.Context#toSql^~}}
> [https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/rel/rel2sql/SqlImplementor.java#L869],
> the operandList is empty because that there is with no argument in aggCall.
> Second, while validating the result SqlNode, in the method
> org.apache.calcite.sql.fun.SqlCountAggFunction#deriveType
> [https://github.com/apache/calcite/blob/8327e674e7f0a768d124fa37fd75cda4b8a35bb6/core/src/main/java/org/apache/calcite/sql/fun/SqlCountAggFunction.java#L79],
> the result of function call {{call.isCountStar() is false}}, because there is
> no operand in {{call. While actually this is a count star call.}}
>
> *How to solve this problem?*
> I think we can solve it either in the first or second step, but solving it in
> the second step is more appropriate because SqlNode converted from RelNode
> should be same with the result parsed from sql string possibly.
>
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