感谢大佬，我找到了。 所以说SQL类的内建函数实际上使用的是calcite的能力，而flink自己的内建函数是在table api中使用
> 2023年11月24日 17:07，Xuyang <[email protected]> 写道： > > Hi, > 关于你举的例子，如果编译了源码的话，可以在FlinkSqlParserImpl这个被动态生成的词法解析器类中找到PostfixRowOperator方法，大致是通过识别到IS > NOT NULL这三个关键字，转化为Calcite的这个内置函数SqlStdOperatorTable.IS_NOT_NULL > > > > > -- > > Best！ > Xuyang > > > > > > 在 2023-11-24 15:15:04，"jinzhuguang" <[email protected]> 写道： >> flink 1.18.0 >> >> >> 例如我写下一条SQL： >> select * from KafkaTable where id is not null; >> >> IS NOT NULL应该属于系统内建函数，于是我找到相关代码： >> >> public static final BuiltInFunctionDefinition IS_NOT_NULL = >> BuiltInFunctionDefinition.newBuilder() >> .name("isNotNull") >> .kind(SCALAR) >> >> .inputTypeStrategy(wildcardWithCount(ConstantArgumentCount.of(1))) >> >> .outputTypeStrategy(explicit(DataTypes.BOOLEAN().notNull())) >> .build(); >> >> 发现他的name是“ isNotNull”，和“is not null”对应不上。并且经过实际测验，确实证实了我的猜想： >> >> DEBUG org.apache.flink.table.module.ModuleManager [] - >> Cannot find FunctionDefinition 'is not null' from any loaded modules. >> >> >> 所以我很疑惑，SQL到底是在哪里找到了”is not null”这个函数的呢？ >> >> 以下是调用栈： >> @org.apache.flink.table.planner.catalog.FunctionCatalogOperatorTable.lookupOperatorOverloads() >> at >> org.apache.calcite.sql.util.ChainedSqlOperatorTable.lookupOperatorOverloads(ChainedSqlOperatorTable.java:69) >> at >> org.apache.calcite.sql.SqlUtil.lookupSubjectRoutinesByName(SqlUtil.java:609) >> at >> org.apache.calcite.sql.SqlUtil.lookupSubjectRoutines(SqlUtil.java:535) >> at org.apache.calcite.sql.SqlUtil.lookupRoutine(SqlUtil.java:486) >> at org.apache.calcite.sql.SqlOperator.deriveType(SqlOperator.java:595) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl$DeriveTypeVisitor.visit(SqlValidatorImpl.java:6302) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl$DeriveTypeVisitor.visit(SqlValidatorImpl.java:6287) >> at org.apache.calcite.sql.SqlCall.accept(SqlCall.java:161) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl.deriveTypeImpl(SqlValidatorImpl.java:1869) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl.deriveType(SqlValidatorImpl.java:1860) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl.validateWhereOrOn(SqlValidatorImpl.java:4341) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl.validateWhereClause(SqlValidatorImpl.java:4333) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl.validateSelect(SqlValidatorImpl.java:3606) >> at >> org.apache.calcite.sql.validate.SelectNamespace.validateImpl(SelectNamespace.java:64) >> at >> org.apache.calcite.sql.validate.AbstractNamespace.validate(AbstractNamespace.java:89) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl.validateNamespace(SqlValidatorImpl.java:1050) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl.validateQuery(SqlValidatorImpl.java:1025) >> at org.apache.calcite.sql.SqlSelect.validate(SqlSelect.java:248) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl.validateScopedExpression(SqlValidatorImpl.java:1000) >> at >> org.apache.calcite.sql.validate.SqlValidatorImpl.validate(SqlValidatorImpl.java:749) >> at >> org.apache.flink.table.planner.calcite.FlinkPlannerImpl.org$apache$flink$table$planner$calcite$FlinkPlannerImpl$$validate(FlinkPlannerImpl.scala:196) >> at >> org.apache.flink.table.planner.calcite.FlinkPlannerImpl.validate(FlinkPlannerImpl.scala:117) >> at >> org.apache.flink.table.planner.operations.SqlNodeToOperationConversion.convert(SqlNodeToOperationConversion.java:261) >> at >> org.apache.flink.table.planner.delegation.ParserImpl.parse(ParserImpl.java:106) >> at >> org.apache.flink.table.gateway.service.operation.OperationExecutor.executeStatement(OperationExecutor.java:187) >> at >> org.apache.flink.table.gateway.service.SqlGatewayServiceImpl.lambda$executeStatement$1(SqlGatewayServiceImpl.java:212) >> at >> org.apache.flink.table.gateway.service.operation.OperationManager.lambda$submitOperation$1(OperationManager.java:119) >> at >> org.apache.flink.table.gateway.service.operation.OperationManager$Operation.lambda$run$0(OperationManager.java:258) >> at >> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) >> at java.util.concurrent.FutureTask.run(FutureTask.java:266) >> at >> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) >> at java.util.concurrent.FutureTask.run(FutureTask.java:266) >> at >> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) >> at >> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) >> at java.lang.Thread.run(Thread.java:750)
