Select within a Select using decode

I am novice at SQL, and I am trying to get only the lab test of "GLUCOSE" out. The following code works great, but pulls all of the tests. How do I return just one test? I have tried a select within a select, but I keep getting errors. Thanks for any help.

SELECT cci.PATCOMMON.NAME,
cci.CRITICALVALUESNOTIFICATION_201.patid, cci.CRITICALVALUESNOTIFICATION_201.key,
max(decode(cci.CRITICALVALUESNOTIFICATION_201.tag, 5,cci.CRITICALVALUESNOTIFICATION_201.data)) "Lab Test",
max(decode(cci.CRITICALVALUESNOTIFICATION_201.tag, 1,cci.CRITICALVALUESNOTIFICATION_201.data)) "Time Lapse Date",
max(decode(cci.CRITICALVALUESNOTIFICATION_201.tag, 56,cci.CRITICALVALUESNOTIFICATION_201.data)) "Lab to Phys by Nursing",
max(decode(cci.CRITICALVALUESNOTIFICATION_201.tag, 57,cci.CRITICALVALUESNOTIFICATION_201.data)) "Physian to Nursing",
max(decode(cci.CRITICALVALUESNOTIFICATION_201.tag, 39,cci.CRITICALVALUESNOTIFICATION_201.data)) "Lab to Physician",
cci.NAME_517.patid, cci.PATID_3592.patid, cci.SSN_518.patid
FROM cci.CRITICALVALUESNOTIFICATION_201, cci.NAME_517, cci.PATID_3592, cci.SSN_518, cci.PATCOMMON
WHERE
cci.CRITICALVALUESNOTIFICATION_201.patid = cci.NAME_517.patid AND
cci.CRITICALVALUESNOTIFICATION_201.patid = cci.PATID_3592.patid AND
cci.CRITICALVALUESNOTIFICATION_201.patid = cci.SSN_518.patid AND
cci.CRITICALVALUESNOTIFICATION_201.patid = cci.PATCOMMON.patid
GROUP by cci.PATCOMMON.NAME, cci.CRITICALVALUESNOTIFICATION_201.key, cci.CRITICALVALUESNOTIFICATION_201.patid, cci.NAME_517.patid, cci.PATID_3592.patid, cci.SSN_518.patid