请分析为何两个语句执行效率不一样：
语句一：
select ac010_.AAC001 as x0_0_, ab011_.AAB001 as x1_0_, kcb82_.AAC001 as x2_0_,kca93_.AAC001 as x3_0_, kca93_.AAE001 as x3_1_ from AB01 ab011_ , AC01 ac010_, KCB8 kcb82_, KCA9 kca93_ whereab011_.AAB001=ac010_.AAB001
andab011_.AAB001='01001602'
andac010_.AAC001=kcb82_.AAC001
and kcb82_.EKC101='0'
and ab011_.AAB001 = ac010_.AAB001
and ac010_.AAC001=kca93_.AAC001
and kca93_.AAE001=F_GETCHALKYEAR('2')
and kca93_.AKC021'00'
语句二：
select ac010_.AAC001 as x0_0_, ab011_.AAB001 as x1_0_, kcb82_.AAC001 as x2_0_
,kca93_.AAC001 as x3_0_, kca93_.AAE001 as x3_1_
from AB01 ab011_ , AC01 ac010_, KCB8 kcb82_, KCA9 kca93_
where
ab011_.AAB001=ac010_.AAB001
andab011_.AAB001='01001602'
andac010_.AAC001=kcb82_.AAC001
and kcb82_.EKC101='0'
and ac010_.AAC001=kca93_.AAC001
and kca93_.AAE001=F_GETCHALKYEAR('2')
and kca93_.AKC021'00'
语句二与语句一相比，仅仅少了一句ab011_.AAB001=ac010_.AAB001 且这个条件在语句一中重复写了一遍而已。语句一的解析代价是21，语句二的解析代价是390。
请问那位能解释这个问题？
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