Magento组合查询语句的Complex_filter和Filter

当我们在Magento中查询一条记录时, 能用filter函数来缩小结果查询范围，相对于数据库中where子句.
基础filter使用EQUAL操作和AND操作，例如，查询产品Where子句: type=simple AND set=39
Example:
<urn:catalogProductList soapenv:encodingStyle=”http://schemas.xmlsoap.org/soap/encoding/”>
    <sessionId xsi:type=”xsd:string”>c9f1ca71de1da4202c84bf90f6df51cf</sessionId>
    <filters xsi:type=”urn:filters”>
        <filter xsi:type=”urn:associativeArray” soapenc:arrayType=”urn:associativeEntity[]“>
            <item>
                <key>type</key>
                <value>simple</value>
            </item>
            <item>
                <key>set</key>
                <value>39</value>
            </item>
        </filter>
    </filters>
    <storeView xsi:type=”xsd:string”></storeView>
</urn:catalogProductList>

使用复合高级过滤器complex filter能完成更复杂的查询语句

例如, 查询顾客customers用了两个复合过滤器complex filters: 

store_id=0 AND created_at>2012-05-13 06:11:00

Example:
<urn:customerCustomerList soapenv:encodingStyle=”http://schemas.xmlsoap.org/soap/encoding/”>
    <sessionId xsi:type=”xsd:string”>c9f1ca71de1da4202c84bf90f6df51cf</sessionId>
    <filters xsi:type=”urn:filters”>
        <complex_filter xsi:type=”urn:complexFilterArray” soapenc:arrayType=”urn:complexFilter[]“>
            <item>
                <key>store_id</key>
                <value>
                    <key>eq</key>
                    <value>0</value>
                </value>
            </item>
            <item>
                <key>created_at</key>
                <value>
                    <key>gt</key>
                    <value>2012-05-13 06:11:00</value>
                </value>
            </item>
        </complex_filter>
    </filters>
</urn:customerCustomerList>

重点：complex filter还能用其他的语句AND操作，例如: eq (equals)等于, neq (not equals)不等于, gt (greater than)大于, lt (less than)小于, 等等还有：

from	returns rows that are after this value (datetime only)
to	returns rows that are before this value (datetime only)
eq	returns rows equal to this value
neq	returns rows not equal to this value
like	returns rows that match this value (with % as a wildcard)
nlike	returns rows that do not match this value (with % as a wildcard)
in	returns rows where the value is in this array (pass an array in)
nin	returns rows where the value is not in this array (pass an array in)
is	unsure
null	returns rows that are null
notnull	returns rows that are not null
moreq	unsure
gt	returns rows greater than this value
lt	returns rows less than this value
gteq	returns rows greater than or equal to this value
lteq	returns rows less than or equal to this value
finset	unsure