SELECTtname,SUM ( A.nnum ) nnum,A.ddate,A.pk_deptdoc,A.pk_calbody,A.deptname 
FROM(SELECT A.ddate,A.pk_calbody,A.pk_deptdoc,A.nnum,b.target_name AS tname,d.deptname FROMkpi_gatherA JOIN kpi_target b ON A.pk_target = b.pk_targetLEFT JOIN bd_deptdoc d ON d.pk_deptdoc = A.pk_deptdoc WHEREA.dr = 0 AND b.dr = 0 AND A.pk_calbody = '1001B21000000087IIIY' AND ( b.pk_parent <> '0001D006FQ4T0NHCN681' OR b.pk_parent IS NULL ) AND A.ddate LIKE'2024-06%' UNION ALLSELECT A.ddate,A.pk_calbody,NULL  pk_deptdoc,A.nnum,'酸耗' AS tname,NULL deptname FROMkpi_gatherA JOIN kpi_target b ON A.pk_target = b.pk_target WHEREA.dr = 0 AND b.dr = 0 AND A.pk_calbody = '1001B21000000087IIIY' AND b.pk_parent = '0001D006FQ4T0NHCN681' AND A.ddate LIKE'2024-06%' ) A 
GROUP BYA.tname,A.ddate,A.pk_calbody,A.pk_deptdoc,A.deptname 
ORDER BYA.tname DESC

问题描述：pk_deptdoc，deptname 这两个字段只显示第一个字符。

解决方案：是因为用到了UNION ALL，为了两边查询结果一致，我们一般会定一个空值，却没有定义数据类型，所以我们要在程序的sql里加上对应的数据类型比如::::char(20)。