Prevent SQL job running when another job is running

CREATEVIEW myschema.Admin_RunningSQLJobs
AS
SELECT job.NAME
    ,job.job_id
    ,job.originating_server
    ,activity.run_requested_date
    ,DATEDIFF(SECOND, activity.run_requested_date, GETDATE()) AS Elapsed
FROM msdb.dbo.sysjobs_view job
JOIN msdb.dbo.sysjobactivity activity ON job.job_id = activity.job_id
JOIN msdb.dbo.syssessions sess ON sess.session_id = activity.session_id
JOIN (
SELECTMAX(agent_start_date) AS max_agent_start_date
FROM msdb.dbo.syssessions
    ) sess_max ON sess.agent_start_date = sess_max.max_agent_start_date
WHERE run_requested_date ISNOTNULL
AND stop_execution_date ISNULL

IFNOTEXISTS(SELECT * FROM myschema.Admin_RunningSQLJobs WHERE name='Pricing - Monthly Rebuild') 
BEGIN
EXEC myschema.Nightly Pricing build
END