把A表的某字段值赋B表中的某字段

CREATE TABLE zhtt_a

(

a VARCHAR2(10),b VARCHAR2(10)

);

CREATE TABLE zhtt_b

(

a VARCHAR2(10),b VARCHAR2(10)

);

insert into zhtt_a values('1','1');

insert into zhtt_a values('12','12');

insert into zhtt_a values('13','13');

insert into zhtt_b values('1','a');

insert into zhtt_b values('12','a');

insert into zhtt_b values('13','a');

select * from zhtt_a;

select * from zhtt_b;

update zhtt_b b set b=(

select b from zhtt_a a where a.a=b.a

)