How to write NOT LIKE subquery with values pulled from table? with wild cards

Question

Hi Expert,

There 2 tables emailinfo(id,email) and keywordinfo(id,keyword). emailinfo contains 80,000 rows and keywordinfo contains 2000 rows.

I want emails from emailinfo table which does not contains keywords from keywordinfo table. eg. SELECT email FROM emailinfo WHERE email not like '%yahoo%' AND email not like '%gmail%'

but this is hardcoded example.and i kept these keywords in keywordinfo table.

In sql procedure i tried for following query,

SELECT EMAIL.email FROM emailinfo EMAIL WHERE ( not exists( Select keyword from keywordinfo where EMAIL.email like '%'+ keyword +'%' )) which take 2 minutes to execute.

I want query like following

SELECT EMAIL.email FROM emailinfo EMAIL where EMAIL.email not like '%' ( SELECT keyword from keywordinfo ) '%'

i know above subquery returns multple rows,but i want something like that.

i have googled many examples but they failed to satisfying my problem

Please help me to write NOT LIKE subquery with values pulled from another table?

Thanks in advance.

Answer 1

I can understand what is desired. You need to know any new keywords missing in your keyword table. But I guess this should be done at the time of insert/update if to be handled efficiently. Otherwise, should be done as a nightly job.

How about

Extract the keyword by finding the string between @ and first . DECLARE @email VARCHAR(50)

SET @email = 'abc@gmail.com'

SELECT LEFT(DomainName, CHARINDEX('.', DomainName) - 1 )
FROM
(
SELECT RIGHT(@email, LEN(@email) - CHARINDEX('@', @email)) DomainName
) A

A very good article by Aaron Bertrand is here

http://www.mssqltips.com/sqlservertip/2657/storing-email-addresses-more-efficiently-in-sql-server/

EDIT.....

I have simulated the exact case on my machine but without the use of NOT LIKE and it worked great

SELECT B.* FROM
(
SELECT [Id], LEFT(DomainName, CHARINDEX('.', DomainName) - 1 ) keyword, [EmailAddress]
FROM
(
SELECT Id, RIGHT(EmailAddress, LEN(EmailAddress) - CHARINDEX('@', EmailAddress)) DomainName, [EmailAddress]
FROM [dbo].[EmailAddress]
) A
) B
LEFT JOIN [dbo].[keyword] AS K
ON B.keyword = [K].[keywords]
WHERE K.[id] IS NULL

How to write NOT LIKE subquery with values pulled from table? with wild cards

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