不影响数据的情况下，oracle中将varchar2变成clob类型的语句

//先将需要修改的字段改名进行备份

alter  table CASE_DOCU_SIX_ORDER_CIACT rename  column  ILLEGAL_FACTS  to  ILLEGAL_FACTS1;

//新建一个字段，long类型，由varchar2变成 clob需要以long过度 alter  table CASE_DOCU_SIX_ORDER_CIACT add ILLEGAL_FACTS long;

//复制备份字段的数据到指定字段 update  CASE_DOCU_SIX_ORDER_CIACT set  ILLEGAL_FACTS = ILLEGAL_FACTS1 ;

//修改指定字段的类型，将long变成clob alter  table  CASE_DOCU_SIX_ORDER_CIACT  modify(ILLEGAL_FACTS clob);

//修改完毕，删除备份字段即可 alter table CASE_DOCU_SIX_ORDER_CIACT drop COLUMN ILLEGAL_FACTS1;

或者

alter table CASE_DOCU_SIX_ORDER_CIACT add ILLEGAL_FACTS1 clob; update CASE_DOCU_SIX_ORDER_CIACT set ILLEGAL_FACTS1 = ILLEGAL_FACTS; alter table CASE_DOCU_SIX_ORDER_CIACT drop column ILLEGAL_FACTS; alter table CASE_DOCU_SIX_ORDER_CIACT rename column ILLEGAL_FACTS1 to ILLEGAL_FACTS;