使用MySQL一个表中的字段更新另一个表中字段
1,修改更新1列
update student s, city c set s.city_name = c.name where s.city_code = c.code;
2,修改多个列
update a, b set a.title=b.title, a.name=b.name where a.id=b.id
3.子查询
update student s set city_name = (select name from city where code = s.city_code);
oracle查询报这个错误:single-rowsubqueryreturnsmorethanonerow怎么解决?
数据库按照你的条件查询有多个重复的数据。
例如:
UPDATE "SYS_ROLE" A SET A ."DEPT_ID" = ( SELECT c."id" FROM "his_department_info" c WHERE c."dept_name" = A ."ROLE_NAME"
如果以上sql语句报single-rowsubqueryreturnsmorethanonerow的错误,说明c表”dept_name”和A表.”ROLE_NAME”的这两个字段数据重复