MySQL用值更新外键

Question

I have two tables:

ANIMALS
---------
id
name
specie_name
id_specie

SCPECIE
---------
id
specie_name

In Animals table I have all values except id_specie. How can I update rows in animals to get ids from table Specie by comparing specie_name from both tables?

Answer 1

Join the two tables. Try this:

UPDATE Animals a INNER JOIN SPECIE b
        on a.specie_name =  b.specie_name
SET    a.id_specie = b.id

FOR REFERENCE

Answer 2

UPDATE ANIMALS SET id_specie = (SELECT id FROM SPECIE WHERE specie_name = ANIMALS.specie_name)