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Any way to select without causing locking in MySQL?

Query:

SELECT COUNT(online.account_id) cnt from online;

But online table is also modified by an event, so frequently I can see lock by running show processlist.

Is there any grammar in MySQL that can make select statement not causing locks?

And I've forgotten to mention above that it's on a MySQL slave database.

After I added into my.cnf:transaction-isolation = READ-UNCOMMITTED the slave will meet with error:

Error 'Binary logging not possible. Message: Transaction level 'READ-UNCOMMITTED' in InnoDB is not safe for binlog mode 'STATEMENT'' on query

So, is there a compatible way to do this?

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Found an article titled "MYSQL WITH NOLOCK"

https://web.archive.org/web/20100814144042/http://sqldba.org/articles/22-mysql-with-nolock.aspx

in MS SQL Server you would do the following:

SELECT * FROM TABLE_NAME WITH (nolock)

and the MYSQL equivalent is

SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED ;
SELECT * FROM TABLE_NAME ;
SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ ;

EDIT

Michael Mior suggested the following (from the comments)

SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED ;
SELECT * FROM TABLE_NAME ;
COMMIT ;

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