Question

I have two mysql table

Table 1

id email  other fields

Table 2

id email other fields 

where id for table1 is auto increment mysql column. and in table 2 id is only primary key not NULL .

some how the id for table 2 had gone wrong.
Now both tables are having some records and I want to make id in table 2 same as table 1.

let’s take an example

Table 1 have

1 [e-mail]
2 [e-mail] 

Table 2 have

1 [e-mail]
2 [e-mail] 

if I fire query

update 
  table2 
set 
  id=(select id from table 1 where email="[e-mail]") 
where 
  email = "[e-mail]"

I will get error because table 2 is already having id value of 2.
now how can I solve this problem ?

I want id of table2 same as table1 based on email.

Answer 1

How about this :

update table2 set email=(
case
when email='[e-mail]' Then '[e-mail]'
when email ='[e-mail]' Then '[e-mail]'
end)