I have two tables as below.
I want to update table_a.fid to table_b.id when table_a.name=table_b.name and table_a.value=table_b.value and table_b.id is not set to other table_a.fid

table_a (a):

id(int) name(varchar) value(varchar) fid(int)
1       name_a        value_1        0
2       name_a        value_1        0
3       name_a        value_1        0
4       name_b        value_2        0
5       name_c        value_3        0

table_b (b):

id(int) name(varchar) value(varchar)
1       name_a        value_1
2       name_a        value_1
3       name_b        value_2
4       name_b        value_2

table_a expected results:

id name    value   fid
1  name_a  value_1  1 // b.id(1,2) matched, so set the first b.id(1) to a.fid(1)
2  name_a  value_1  2 // b.id(1,2) matched and b.id(1) already set to a.fid(1), so set the second b.id(2) to a.fid(2)
3  name_a  value_1  0 // b.id(1,2) matched and b.id(1,2) already set to a.fid(1,2), so is 0
4  name_b  value_2  3 // b.id(3,4) matched. so set the first b.id(3) to a.fid
5  name_c  value_3  0 // b not matched