<!-- 此处使用if比较是否相等 -->

范例一：

<select id="queryOrderListPage" parameterType="java.util.Map"
		resultType="java.util.Map">
		SELECT
		EDU_ORDERS.ORDER_ID as orderId,
		EDU_ORDERS.ORDER_NO as orderNo,
		EDU_ORDERS.USER_ID as userId,
		EDU_ORDERS.SUM_MONEY as sumMoney,
		EDU_ORDERS.STATES as states,
		EDU_ORDERS.CREATE_TIME as createTime,
		EDU_ORDERS.PAY_TIME as payTime,
		EDU_ORDERS.PAY_TYPE as payType,
		EDU_ORDERS.out_trade_no as outTradeNo,
		EDU_USER.EMAIL as email,
		EDU_USER.MOBILE as mobile
		FROM EDU_ORDERS
		LEFT JOIN EDU_USER ON
		EDU_USER.USER_ID = EDU_ORDERS.USER_ID
		left join edu_trxorder_detail on
		EDU_ORDERS.ORDER_NO = edu_trxorder_detail.request_id
		<where>
			<if test="e.keyWord!=null and e.keyWord!=''">
				AND (EDU_ORDERS.ORDER_NO LIKE
				CONCAT('%',#{e.keyWord},'%')
				OR EDU_USER.EMAIL LIKE
				CONCAT('%',#{e.keyWord},'%')
				OR EDU_USER.MOBILE LIKE
				CONCAT('%',#{e.keyWord},'%')
				OR EDU_ORDERS.out_trade_no LIKE
				CONCAT('%',#{e.keyWord},'%')
				)
			</if>
			<if test="e.beginCreateTime!=null and e.beginCreateTime!=''">
				AND EDU_ORDERS.CREATE_TIME >= #{e.beginCreateTime}
			</if>
			<if test="e.endCreateTime!=null and e.endCreateTime!=''">
				AND <![CDATA[EDU_ORDERS.CREATE_TIME <= #{e.endCreateTime}]]>
			</if>
			<if test="e.beginPayTime!=null and e.beginPayTime!=''">
				AND EDU_ORDERS.PAY_TIME >= #{e.beginPayTime}
			</if>
			<if test="e.endPayTime!=null and e.endPayTime!=''">
				AND <![CDATA[ EDU_ORDERS.PAY_TIME <= #{e.endPayTime}]]>
			</if>
			<if test="e.userId>0">
				AND EDU_ORDERS.USER_ID=#{e.userId}
			</if>
			<if test="e.states!=null and e.states!='' and e.states!='all'.toString()">
				AND EDU_ORDERS.STATES=#{e.states}
			</if>
			<if test="e.payType!=null and e.payType!=''and e.payType!='CTOC'.toString()">
				AND EDU_ORDERS.PAY_TYPE = #{e.payType}
			</if>
			<if test="e.payType!=null and e.payType!=''and e.payType=='CTOC'.toString()">
				AND (EDU_ORDERS.PAY_TYPE = 'ALIPAY' OR EDU_ORDERS.PAY_TYPE = 'WEIXIN')
			</if>
			<if test="e.courseId!=null and e.courseId!=0">
				AND edu_trxorder_detail.course_id = #{e.courseId}
			</if>
		</where>
		group by EDU_ORDERS.ORDER_ID
		ORDER BY EDU_ORDERS.CREATE_TIME DESC
	</select>

范例二：

mybatis 映射文件中，if标签判断字符串相等，两种方式：
因为mybatis映射文件，是使用的ognl表达式，所以在判断字符串isComplete变量是否是字符串Y的时候

<if test="isComplete=='Y'.toString()">

或者使用下面的写法
<if test = 'isComplete== "Y"'>

注意：不能使用以下方式

<if test="isComplete=='Y'">
  and 1=1
</if>

因为mybatis会把'Y'解析为字符，java是强类型语言，所以不能这样写。