fix(UserBalanceLog): 优化 SQL 参数空值校验

- 在多个 SQL 查询条件中添加参数非空且非空字符串判断
- 防止空字符串导致的错误匹配或异常
- 统一调整语句格式，保持代码规范和可读性
- 优化关联查询时参数过滤逻辑，提升查询准确性

src/main/java/com/gxwebsoft/common/system/mapper/xml/UserBalanceLogMapper.xml

@@ -5,7 +5,7 @@
     <!-- 关联查询sql -->
     <sql id="selectSql">
         SELECT a.*,
-               b.nickname,b.avatar,b.phone
+               b.nickname, b.avatar, b.phone
         FROM sys_user_balance_log a
         LEFT JOIN sys_user b ON a.user_id = b.user_id
         <where>
@@ -18,7 +18,7 @@
             <if test="param.scene != null">
               AND a.scene = #{param.scene}
             </if>
-            <if test="param.sceneMultiple != null">
+            <if test="param.sceneMultiple != null and param.sceneMultiple != ''">
               AND a.scene IN
               <foreach collection="param.sceneMultiple.split(',')" item="item" separator="," open="(" close=")">
                 #{item}
@@ -30,16 +30,16 @@
             <if test="param.balance != null">
                 AND a.balance = #{param.balance}
             </if>
-            <if test="param.describe != null">
+            <if test="param.describe != null and param.describe != ''">
                 AND a.describe LIKE CONCAT('%', #{param.describe}, '%')
             </if>
-            <if test="param.remark != null">
+            <if test="param.remark != null and param.remark != ''">
                 AND a.remark LIKE CONCAT('%', #{param.remark}, '%')
             </if>
             <if test="param.sortNumber != null">
                 AND a.sort_number = #{param.sortNumber}
             </if>
-            <if test="param.comments != null">
+            <if test="param.comments != null and param.comments != ''">
                 AND a.comments LIKE CONCAT('%', #{param.comments}, '%')
             </if>
             <if test="param.status != null">
@@ -51,7 +51,7 @@
             <if test="param.deleted == null">
                 AND a.deleted = 0
             </if>
-            <if test="param.merchantCode != null">
+            <if test="param.merchantCode != null and param.merchantCode != ''">
                 AND a.merchant_code LIKE CONCAT('%', #{param.merchantCode}, '%')
             </if>
             <if test="param.createTimeStart != null">
@@ -60,7 +60,7 @@
             <if test="param.createTimeEnd != null">
                 AND a.create_time &lt;= #{param.createTimeEnd}
             </if>
-            <if test="param.keywords != null">
+            <if test="param.keywords != null and param.keywords != ''">
               AND (
               a.user_id = #{param.keywords}
               OR b.nickname LIKE CONCAT('%', #{param.keywords}, '%')