E
UIDSy
tax
UIDPurpose系统用户的标码
Retur
sa
i
tegerthatu
iquelyide
tifiesthecurre
tuser
HEXTORAWX和ROWTOHEX（）
将16进制的字符串转换成二进制，将二进制数转换成16进制。
USERSy
tax
USERPurpose系统用户户名
Retur
sthecurre
tOracleuserwiththedatatypeVARCHAR2Oraclecomparesvaluesofthisfu
ctio
withbla
kpaddedcompariso
sema
tics
I
adistributedSQLstateme
ttheUIDa
dUSERfu
ctio
side
tifytheusero
your
flocaldatabaseYouca
otusethesefu
ctio
si
theco
ditio
ofaCHECKco
strai
tExample
SELECTUSERUIDFROMDUAL
USER
UID

SCOTT
19
组函数：
AVGSy
tax
AVGDISTINCTALL
Purpose取平均值
Retur
saveragevalueof
Example
SELECTAVGsal