Update two table fields value using MySQL query - php

Question

I have two MySQL table with contain values like
table1
id email_id
===========
1 abc#xyz.com
2 bbc#xy.com
3 gty#xyz.com
4 iut#xyz.com
5 tyk#xy.com
table2
id name email_id
===========
1 abc abc#xy.com
2 bbc bbc#xy.com
3 gty gty#xy.com
4 iut iut#xy.com
5 tyk tyk#xy.com
6 tyr tyr#xy.com
7 iut iut#xy.com
Result
table2
id name email_id
===========
1 abc abc#xyz.com
2 bbc bbc#xy.com
3 gty gty#xyz.com
4 iut iut#xyz.com
5 tyk tyk#xy.com
6 tyr tyr#xy.com
7 iut iut#xyz.com
You can see in my first table is a combination of #xy.com and #xyz.com. So i need to change all #xy.com to #xyz.com in table2 whether if table1 is same #xyz.com.
Example: case1- in table1 abc#xyz.com is available and its #xyz format, so in table2 i needs to change it as abc#xyz.com
case2- in table1 bbc#xy.com is available and its in #xy format, So in table2 i need not change bbc#xyz.com. i can leave it as it is.
i think you understood my issue and please give me a mysql query for solve it.Thanks in advance

Answer 1

You can join together table1 and table2 and then compare the length of the email addresses for each id. Since you want to conditionally replace the #xy format with the #xyz format, you can simply choose the longer email address to retain in the query.
SELECT t2.id, t2.name,
CASE WHEN CHAR_LENGTH(t2.email_id) > CHAR_LENGTH(COALESCE(t1.email_id, ''))
THEN t2.email_id ELSE t1.email_id END AS email_id
FROM table2 t2 LEFT JOIN table1 t1 ON t2.id = t1.id

Answer 2

i had written in sql server
create table #stack_table1(id int identity(1,1),
email_id varchar(1000))
create table #stack_table2(id int ,
name varchar(50),
email_id varchar(1000)
)
insert into #stack_table1(email_id)
(select ('abc#xyz.com')
union
select ('bbc#xy.com')
union
select ('gty#xyz.com')
union
select ('iut#xyz.com')
union
select ('tyk#xy.com')
)
insert into #stack_table2(id,name,email_id)
(
select 1,'abc','abc#xy.com'
union
select 2,'bbc','bbc#xy.com'
union
select 3,'gty','gty#xy.com'
union
select 4,'iut','iut#xy.com'
union
select 5,'tyk','tyk#xy.com'
union
select 6,'tyr','tyr#xy.com'
union
select 7,'iut','iut#xy.com'
)
select * from #stack_table1
select * from #stack_table2
tables were created
update statement will be as follows
UPDATE st2
SET st2.email_id = st1.email_id
FROM #stack_table1 st1
JOIN #stack_table2 st2 ON st2.NAME = substring(st1.email_id, 1, CHARINDEX('#', st1.email_id, 1) - 1)
if only select query needed please use this
SELECT st2.id
,st2.NAME
,coalesce(st1.email_id, st2.email_id)
FROM #stack_table1 st1
RIGHT JOIN #stack_table2 st2 ON st2.NAME = substring(st1.email_id, 1, CHARINDEX('#', st1.email_id, 1) - 1)