SELECT NVL(T11.DEPID, 'NULL'), NVL(T11.PARDEPID, 'NULL'), NVL(T11.DEPNAME, 'NULL') FROM (SELECT DISTINCT DEPID, PARDEPID, DEPNAME, DEPCODE, SPECIALTYCODE, ROTAID FROM SYS_DEPARTMENT START WITH DEPID IN (SELECT DEPID FROM SYS_SM_ROLEDEP WHERE ROLEID IN (SELECT ROLEID FROM SYS_USERQUARTERS WHERE USERID = '1')) CONNECT BY PARDEPID = PRIOR DEPID ORDER BY ORDERNO) T11
今天在数据库执行以上代码的时候 出现“ORA-01791:不是SElECTed表达式”这个错误
经分析,如果在ORDER BY中指定多个列,结果将先按照子句中的第一个列排序,然后第二个,依此类推
在 SELECT中未出现的列名也可用于ORDER BY 子句中,主要TABLE中有就行,但如果SELECT子句中出现了DISTINCT关键字,则只能用出现过的列名,而且如果SELECT子句中使用了任何运算符,在ORDER BY 子句中必须保持和SELECT子句中表达式完全一致,否则出现ORA-01791 ERROR
所以将对应字段添加上就可以了
SELECT NVL(T11.DEPID, 'NULL'), NVL(T11.PARDEPID, 'NULL'), NVL(T11.DEPNAME, 'NULL') FROM (SELECT DISTINCT DEPID, PARDEPID, DEPNAME, DEPCODE, SPECIALTYCODE, ROTAID, ORDERNO FROM SYS_DEPARTMENT START WITH DEPID IN (SELECT DEPID FROM SYS_SM_ROLEDEP WHERE ROLEID IN (SELECT ROLEID FROM SYS_USERQUARTERS WHERE USERID = '1')) CONNECT BY PARDEPID = PRIOR DEPID ORDER BY ORDERNO) T11