把varchar转成text不能直接转,应该这样,例:create table COPTC(TC201 varchar(10) null)
insert into COPTC values('sdf')alter table COPTC add tmp text nullupdate COPTC set tmp=TC201alter table COPTC drop TC201alter table COPTC add TC201 text nullupdate COPTC set TC201=tmpalter table COPTC drop tmp
insert into COPTC values('sdf')alter table COPTC add tmp text nullupdate COPTC set tmp=TC201alter table COPTC drop TC201alter table COPTC add TC201 text nullupdate COPTC set TC201=tmpalter table COPTC drop tmp
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