需求: PI6000.AUT_OM_JXSQ_DD表中GLXX字段类型为CLOB,需要修改为VARCHARALTER TABLE PI6000.AUT_OM_JXSQ_DD ADD(C VARCHAR2(4000));UPDATE PI6000.AUT_OM_JXSQ_DD SET C = GLXX;ALTER TABLE PI6000.AUT_OM_JXSQ_DD DROP COLUMN GLXX;ALTER TABLE PI6000.AUT_OM_JXSQ_DD RENAME COLUMN C TO GLXX;