t1:
code value
---------------
B0006 2123629.03
B0005 0
B0007 456573.38
t2:
code value
---------------
B0006 2123629.03
1.select t1.code_t1 code_t1,
t1.value_t1 value_t1,
t2.code_t2 code_t2,
t2.value_t2 value_t2
from t1
left join t2
on t1.code_t1 = 'B0006';code_t1 value_t1 code_t2 value_t2
--------------------------------------------
B0006 2123629.03 B0006 2123629.03
B0005 0
B0007 456573.38 2.select t1.code_t1 code_t1,
t1.value_t1 value_t1,
t2.code_t2 code_t2,
t2.value_t2 value_t2
from t1
left join t2
on t1.code_t1 = t2.code_t2
where t1.code_t1 = 'B0006'code_t1 value_t1 code_t2 value_t2
--------------------------------------------
B0006 2123629.03 B0006 2123629.03
3.select t1.code_t1 code_t1,
t1.value_t1 value_t1,
t2.code_t2 code_t2,
t2.value_t2 value_t2
from t1
left join t2
on t1.code_t1 = t2.code_t2
and t1.code_t1 = 'B0006'code_t1 value_t1 code_t2 value_t2
--------------------------------------------
B0006 2123629.03 B0006 2123629.03
B0005 0
B0007 456573.38 4.select t1.code_t1 code_t1,
t1.value_t1 value_t1,
t2.code_t2 code_t2,
t2.value_t2 value_t2
from t1
left join t2
on t1.code_t1 = t2.code_t2
and t2.code_t2 = 'B0006'code_t1 value_t1 code_t2 value_t2
--------------------------------------------
B0006 2123629.03 B0006 2123629.03
B0005 0
B0007 456573.38
可以解释一下这些结果产生的原理吗?
code value
---------------
B0006 2123629.03
B0005 0
B0007 456573.38
t2:
code value
---------------
B0006 2123629.03
1.select t1.code_t1 code_t1,
t1.value_t1 value_t1,
t2.code_t2 code_t2,
t2.value_t2 value_t2
from t1
left join t2
on t1.code_t1 = 'B0006';code_t1 value_t1 code_t2 value_t2
--------------------------------------------
B0006 2123629.03 B0006 2123629.03
B0005 0
B0007 456573.38 2.select t1.code_t1 code_t1,
t1.value_t1 value_t1,
t2.code_t2 code_t2,
t2.value_t2 value_t2
from t1
left join t2
on t1.code_t1 = t2.code_t2
where t1.code_t1 = 'B0006'code_t1 value_t1 code_t2 value_t2
--------------------------------------------
B0006 2123629.03 B0006 2123629.03
3.select t1.code_t1 code_t1,
t1.value_t1 value_t1,
t2.code_t2 code_t2,
t2.value_t2 value_t2
from t1
left join t2
on t1.code_t1 = t2.code_t2
and t1.code_t1 = 'B0006'code_t1 value_t1 code_t2 value_t2
--------------------------------------------
B0006 2123629.03 B0006 2123629.03
B0005 0
B0007 456573.38 4.select t1.code_t1 code_t1,
t1.value_t1 value_t1,
t2.code_t2 code_t2,
t2.value_t2 value_t2
from t1
left join t2
on t1.code_t1 = t2.code_t2
and t2.code_t2 = 'B0006'code_t1 value_t1 code_t2 value_t2
--------------------------------------------
B0006 2123629.03 B0006 2123629.03
B0005 0
B0007 456573.38
可以解释一下这些结果产生的原理吗?
这个问题极深 极深
拿下Oracle认证的我都怀疑能否讲得清