Change table data type: ORA-01439: To change the data type, the column you want to modify must be empty

Re-organized data sometimes imported data types are inconsistent and need to change the data type

/* Modify the name of the original field named areaid_tmp*/
ALTER TABLE sys_area_new rename column areaid to areaid_tmp;

/* Add a field with the same name as the original field name name*/
ALTER TABLE sys_area_new add Areaid integer;

/* Update the original field AREAID_TMP data to the added field areaid*/
update sys_area_new set Areaid=trim (areaid_tmp);

/* After updating, delete the original field areaid_tmp*/
ALTER TABLE sys_area_new drop column areaid_tmp;

System upgrade Thinking