SQL多表查询发生笛卡尔积的问题
selectq T.VEH_NO,
T.VEH_ID,
T.VEH_NAME,
T.VEH_COLOR,
T.VEH_IN_COMP AS COM_ID,
A.PERSON_NAME,
A.PERSON_NUMBER,
(SELECT TEXT FROM T_SYS_COM WHERE ID = T.VEH_IN_COMP) AS VEH_IN_COMP,
DECODE(T.AXLE,'axle1','一轴','axle2','二轴','axle3','三轴') "AXLE"
FROM R_VEHICLE_INFO T,R_PERSON_INFO A
WHERE(1=1)
ORDER BY T.VEH_IN_COMP
本人开发小白基础不熟练,查询出来之后数据多了两倍不止,请高手解答-------------感激不尽