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 create table a
(
 fid int,
 call varchar(20),
 age int
)
create table b
(
 fid int,
 caller varchar(20),
 parentId int
)
select * from a
select * from b
insert into a values(1,null,19)
insert into a values(2,null,20)
insert into b values(1,'a',1)
insert into b values(2,'b',2)
update  a set call =b.caller from b inner join a on a.fid = b.parentId