Het lijkt erop dat dit is wat je wilt. Ik heb de eerste query geüpdatet om de juiste ANSI JOIN te gebruiken syntaxis en vervolgens voor de extra twee zoekopdrachten werden ze samengevoegd via een LEFT JOIN op de stats_host veld:
SELECT s.stats_host,
h.host_name,
s.stats_avgcpu,
s.stats_avgmem,
s.stats_avgswap,
s.stats_avgiowait,
s7.7dayavgcpu,
s7.7dayavgmem,
s7.7dayavgswap,
s7.7dayavgiowait,
s30.30dayavgcpu,
s30.30dayavgmem,
s30.30dayavgswap,
s30.30dayavgiowait
FROM sar_stats s
INNER JOIN sar_hosts h
on s.stats_host = h.host_id
INNER JOIN sar_appgroups a
on h.host_appgroup = a.group_id
and a.group_name = 'Pervasive'
INNER JOIN sar_environments e
on h.host_environment = e.env_id
and e.env_name = 'Staging 2'
LEFT JOIN
(
SELECT s.stats_host,
AVG(s.stats_avgcpu) AS '7dayavgcpu',
AVG(s.stats_avgmem) AS '7dayavgmem',
AVG(s.stats_avgswap) AS '7dayavgswap',
AVG(s.stats_avgiowait) AS '7dayavgiowait'
FROM sar_stats s
WHERE DATE(stats_report_time) BETWEEN DATE_SUB(curdate(), INTERVAL 8 DAY) AND DATE_SUB(curdate(), INTERVAL 1 DAY)
GROUP BY s.stats_host
) s7
on s.stats_host = s7.stats_host
LEFT JOIN
(
SELECT s.stats_host,
AVG(s.stats_avgcpu) AS '30dayavgcpu',
AVG(s.stats_avgmem) AS '30dayavgmem',
AVG(s.stats_avgswap) AS '30dayavgswap',
AVG(s.stats_avgiowait) AS '30dayavgiowait'
FROM sar_stats s
WHERE DATE(s.stats_report_time) BETWEEN DATE_SUB(curdate(), INTERVAL 31 DAY) AND DATE_SUB(curdate(), INTERVAL 1 DAY)
GROUP BY s.stats_host
) s30
on s.stats_host = s30.stats_host
WHERE DATE(s.stats_report_time) = DATE_SUB(curdate(), INTERVAL 1 DAY);