Agregacni dotaz ?

[Karel Král]

Rekneme, ze mam nasledujici zaznamy v tabulce:

rule = 's1_xxx->' ,  bytes=x1, time=t
rule = 's1_xxx<-',   bytes=x2, time=t
rule = 's1_yyy->',   bytes=x3, time=t
rule = 's1_yyy<-',   bytes=x4, time=t
atd pro time=t1

prikaz
SELECT rule, bytes,time FROM table WHERE rule LIKE 's1_xxx%'  AND time >=tx
AND time <=ty

mi vrati pro kazdy cas t vzdy dva zaznamy

rule = 's1_xxx->' ,  bytes=x1, time=t
rule = 's1_xxx<-',   bytes=x2, time=t

problem je jak dotaz rozsirit tak, aby bylo mozno dotaz omezit WHERE rule
LIKE 's1%'  AND time >=tx AND time <=ty a doslo k vraceni opet pouze dvou
zaznamu

rule = 's1_???->' ,  bytes=x1+x3, time=t
rule = 's1_???<-',   bytes=x2+x4, time=t

zrejme nejak pomoci Group, ale nejak se mi nedari.


Dekuji za radu.