MySQL更新表1与表2比较

Question

In my mysql db i've 2 table with same field in both.

I need to update all the records in table2 where table1 had the same id_customer and the fields are not empty.

Example:

table1

id|name|surname|id_customer|email

1|jon|jack|12|hello@me.com

table2

id_customer|name|surname|email

12| |jack|hello@me.com

The query have to update table2 adding "jon" on name

Any idea how to?

Thank you

Answer 1

Try this one -

UPDATE table1 t1
  JOIN table2 t2
    ON t1.customer_id = t2.customer_id
SET
  t2.name = IF(t2.name IS NULL OR t2.name = '', t1.name, t2.name),
  t2.email = IF(t2.email IS NULL OR t2.email = '', t1.email, t2.email),
  t2.sur_name = IF(t2.sur_name IS NULL OR t2.sur_name = '', t1.sur_name, t2.sur_name);

Answer 2

update table2 
set table2.name = table1.name,
table2.email = table1.email,
table2.sur_name = table1.sur_name 
where table2.customer_id = table1.customer_id

I guess it might be better to join on customer_id, if it is available in both tables (as it is example). Moreover if we need to update table1 on basic of table1, then can we update all fields, if yes above query will execute, else you can have a look at CASE clause.