select sys_guid() AS LCID,
(select yhmc from NX_UserInfo where yhbm = a.add_user and rownum < 2) as CJRMC,--这条select语句yhmc字段可能查出来是null，如果为null的话就取a.add_user,请问这里怎么修改？
(select jgbm from pmsadm.yzx_jgdyxx@sc_link where gisjgbm = (select jgmc from NX_UserInfo where yhbm = a.add_user and rownum < 2)) AS CJDW,
to_number(to_char(a.ADD_DATE,'yyyymmdd')) AS CJRQ,
'0' AS YXYWBH,
'0' AS SCYWBH,
to_char(a.TASK_ID) AS DDYWBH,
case a.task_source when 1 then '配网工程电子化移交流程'
when 2 then '基建及大修技改电子化移交流程'
when 5 then '基建及大修技改电子化移交流程' end as LCMC,
case a.TASK_STATUS when '-2' then 1
when '1' then 2
else 0 end as LCZT,
a.MAINTAIN_CONTENT AS YJDSM,
(select yjbdzsl from ext_scdy_yjsl where task_id = a.task_id) as YJBDZSL,
(select yjxlsl from ext_scdy_yjsl where task_id = a.task_id) as YJXLSL,
(select yjbyqsl from ext_scdy_yjsl where task_id = a.task_id) as YJBYQSL,
0 AS YJYHSL,
0 AS YJBJSL,
to_char(a.ADD_DATE,'yyyymmdd') AS FQZJ,
a.add_user as CJRBH,
(select bmmc from NX_UserInfo where yhbm = a.add_user and rownum < 2) as CJBM,
to_number(to_char(a.ADD_DATE,'hhmmss')) AS CJSJ,
a.task_type AS TASK_TYPE
from txwh_feature_mt_app a
查询出来的结果CJRMC会有空值如下图：
------解决思路----------------------
nvl((select yhmc from NX_UserInfo where yhbm = a.add_user and rownum < 2) ,a.add_user) CJRMC