Hi, everyone. I have a question. I would like to ask you a question. Problem Description: I have two tables (streams from kafka),Both tables define rowTime attributes in EVENTTIME table1(EVENTTIME,NEW_EVENT_ID,F4,F6) table2(EVENTTIME,NEW_EVENT_ID,F2,F3) now,I would like to use UNION ALL for two streams and distinct them as follows: Table id_distinct = tableEnv.sqlQuery("select distinct EVENTTIME,NEW_EVENT_IDfrom (select EVENTTIME,NEW_EVENT_ID FROM table1 union all select EVENTTIME,NEW_EVENT_ID FROM table2)"); Question: It will report the following exception. How can I fix this problem? Thank you! Exception in thread "main" java.lang.AssertionError: Type mismatch: rowtype of new rel: RecordType(TIMESTAMP(3) NOT NULL EVENTTIME, VARCHAR(65536) CHARACTER SET "UTF-16LE" COLLATE "ISO-8859-1$en_US$primary" NEW_EVENT_ID) NOT NULL rowtype of set: RecordType(TIMESTAMP(3) NOT NULL EVENTTIME, VARCHAR(65536) CHARACTER SET "UTF-16LE" COLLATE "ISO-8859-1$en_US$primary" NEW_EVENT_ID) NOT NULL at org.apache.calcite.util.Litmus$1.fail(Litmus.java:31) at org.apache.calcite.plan.RelOptUtil.equal(RelOptUtil.java:1857) at org.apache.calcite.plan.volcano.RelSubset.add(RelSubset.java:276) at org.apache.calcite.plan.volcano.RelSet.add(RelSet.java:148) at org.apache.calcite.plan.volcano.VolcanoPlanner.addRelToSet(VolcanoPlanner.java:1633) at org.apache.calcite.plan.volcano.VolcanoPlanner.registerImpl(VolcanoPlanner.java:1579) at org.apache.calcite.plan.volcano.VolcanoPlanner.register(VolcanoPlanner.java:859) at org.apache.calcite.plan.volcano.VolcanoPlanner.ensureRegistered(VolcanoPlanner.java:879) at org.apache.calcite.plan.volcano.VolcanoPlanner.ensureRegistered(VolcanoPlanner.java:1755) at org.apache.calcite.plan.volcano.VolcanoRuleCall.transformTo(VolcanoRuleCall.java:135) at org.apache.calcite.plan.RelOptRuleCall.transformTo(RelOptRuleCall.java:234) at org.apache.calcite.rel.rules.ProjectSetOpTransposeRule.onMatch(ProjectSetOpTransposeRule.java:109) at org.apache.calcite.plan.volcano.VolcanoRuleCall.onMatch(VolcanoRuleCall.java:212) at org.apache.calcite.plan.volcano.VolcanoPlanner.findBestExp(VolcanoPlanner.java:646) at org.apache.calcite.tools.Programs$RuleSetProgram.run(Programs.java:339) at org.apache.flink.table.api.TableEnvironment.runVolcanoPlanner(TableEnvironment.scala:373) at org.apache.flink.table.api.TableEnvironment.optimizeLogicalPlan(TableEnvironment.scala:292) at org.apache.flink.table.api.StreamTableEnvironment.optimize(StreamTableEnvironment.scala:812) at org.apache.flink.table.api.StreamTableEnvironment.translate(StreamTableEnvironment.scala:860) at org.apache.flink.table.api.java.StreamTableEnvironment.toRetractStream(StreamTableEnvironment.scala:305) at org.apache.flink.table.api.java.StreamTableEnvironment.toRetractStream(StreamTableEnvironment.scala:248) at com.nsn.flink.service.DealRegisterFile12.main(DealRegisterFile12.java:80) deng