date return null when cross dn

[Icarus124]

• dble version： 2.19.03
• preconditions ：
  create table datetest(id long) in dn1 and dn2 create table datetest(id long) in dn3 and dn4
• configs： default schema.xml

<table name="datetest" rule="rule_id" dataNode="dn1,dn2"/>
<table name="datetest2" rule="rule_id" dataNode="dn3,dn4"/>

rule.xml

    <tableRule name="rule_id">
        <rule>
            <columns>id</columns>
            <algorithm>hash2</algorithm>
        </rule>
    </tableRule>

    <function name="hashDcar2" class="StringHash">
        <property name="partitionCount">2</property>
        <property name="partitionLength">1</property>
    </function>

server.xml

default

• steps：
  step1. insert into datetest values(108); step2. insert into datetest2 values(108); step3. select A.id from datetest A join datetest2 B on A.id = B.id; step4. select date(A.id) from datetest A join datetest2 B on A.id = B.id;
• expect result：
  1.select A.id from datetest A join datetest2 B on A.id = B.id; get result A.id = 108 2.select date(A.id) from datetest A join datetest2 B on A.id = B.id; get result 2000-01-08
• real result：
  1.select A.id from datetest A join datetest2 B on A.id = B.id; get result A.id = 108 2.select date(A.id) from datetest A join datetest2 B on A.id = B.id; get result null
• supplements：
  1.select date(108) in mysql and dble both get 2000-01-08 guess use date() implement in dble but do not support number like '108' but mysql support select date(108)