九：动态SQL
动态SQL里面的标签类似STRUTS里面的标签，不多说，看看配置就行了！
<sqlMap> <!-- 动态查询1--> <select id="getOrders1" parameterClass="com.air.Account" resultClass="com.air.Product"> SELECT orders.id as id, orders.product as product, orders.customer as customer FROM orders <dynamic prepend=" WHERE "> <isNull property="username">customer IS NOT NULL</isNull> <isNotNull property="username"> orders.customer=#username# </isNotNull> </dynamic> </select> <!-- 动态查询2--> <select id="getOrders2" parameterClass="com.air.Account" resultClass="com.air.Product"> SELECT o.id as id, o.product as product, o.customer as customer FROM orders o <isNotNull property="username"> INNER JOIN user_account a ON o.customer=a.username </isNotNull> <dynamic prepend="where "><isNotEmpty property="groupname" prepend="and " open="(" close=")"> a.groupname=#groupname# </isNotEmpty> </dynamic> </select> <!-- 动态查询3--> <select id="getOrders3" parameterClass="com.air.Product" resultClass="com.air.Product"> SELECT orders.id as id, orders.product as product, orders.customer as customer FROM orders <dynamic prepend="WHERE "> <isNotEmpty property="product" prepend="and" open="(" close=")" > product=#product# </isNotEmpty> <isNotEmpty property="customer" prepend="and" open="(" close=")"> customer=#customer# </isNotEmpty> </dynamic> </select> <!-- 动态查询4--> <select id="getOrders4" parameterClass="com.air.Product" resultClass="com.air.Product"> SELECT * FROM orders <dynamic prepend="WHERE "> <iterate property="keywords" open="(" close=")" conjunction="OR"> product=#keywords[]# </iterate> </dynamic><!-- <dynamic prepend="WHERE product IN ">--><!-- <iterate property="keywords" open="(" close=")" conjunction=","> --><!-- #keywords[]#--><!-- </iterate>--><!-- </dynamic>--> </select></sqlMap>?