union all 出现 > ORA-01789: query block has incorrect number of result columns

		SELECT a.METERBOXID AS row_id, a.epu_name, a.epu_local,b.EPU_PROVINCE,b.epu_city, b.epu_district, b.epu_court ,
		b.SUBSTAINID as SUBSTAIN_ID ,b.OUTGOINGCABINETID,b.branchboxid,b.METERBOXID, b.meterId, 'M0004' as EPU_TYPE
		FROM T_METERBOX a
		JOIN V_USING_TOPO_METERBOX b ON a.METERBOXID = b.METERBOXID

		UNION ALL
		SELECT a.meterId AS row_id,  a.meter_name AS epu_name, a.house_id AS epu_local,b.EPU_PROVINCE,b.epu_city, b.epu_district, b.epu_court ,
		b.SUBSTAINID as SUBSTAIN_ID ,b.OUTGOINGCABINETID,b.branchboxid,b.METERBOXID, b.meterId, 'M0005' as EPU_TYPE,a.CONSUMER_NO
		FROM T_METER a
		JOIN V_USING_TOPO b ON a.METERID = b.METERID

出现这种原因是，B表中有的字段而A表没有。可以通过补空值处理；正确sql如下

		SELECT a.METERBOXID AS row_id, a.epu_name, a.epu_local,b.EPU_PROVINCE,b.epu_city, b.epu_district, b.epu_court ,
		b.SUBSTAINID as SUBSTAIN_ID ,b.OUTGOINGCABINETID,b.branchboxid,b.METERBOXID, b.meterId, 'M0004' as EPU_TYPE,'a.CONSUMER_NO' as CONSUMER_NO
		FROM T_METERBOX a
		JOIN V_USING_TOPO_METERBOX b ON a.METERBOXID = b.METERBOXID

		UNION ALL
		SELECT a.meterId AS row_id,  a.meter_name AS epu_name, a.house_id AS epu_local,b.EPU_PROVINCE,b.epu_city, b.epu_district, b.epu_court ,
		b.SUBSTAINID as SUBSTAIN_ID ,b.OUTGOINGCABINETID,b.branchboxid,b.METERBOXID, b.meterId, 'M0005' as EPU_TYPE,a.CONSUMER_NO
		FROM T_METER a
		JOIN V_USING_TOPO b ON a.METERID = b.METERID

 

 

附加：UNION ALL ：对结果集进行并集操作，不去重；

           UNION ：对结果集进行并集操作，会去重；