feat(export): 添加字段去重逻辑以优化导出功能

在exports.go中实现字段去重，移除完全重复的字段，并确保主表字段优先于副表字段。更新toString函数以支持更多数据类型的格式化，确保导出数据的准确性和一致性。

server/internal/api/exports.go

@@ -242,6 +242,64 @@ func (a *ExportsAPI) create(w http.ResponseWriter, r *http.Request) {
     if len(bad) > 0 {
         logging.JSON("ERROR", map[string]interface{}{"event": "fields_not_whitelisted", "removed": bad})
     }
+    // 字段去重：移除完全重复的字段（包括主表自身的重复）
+    {
+        seen := make(map[string]bool)
+        deduped := make([]string, 0, len(filtered))
+        removed := []string{}
+        for _, tf := range filtered {
+            if seen[tf] {
+                removed = append(removed, tf)
+                continue
+            }
+            seen[tf] = true
+            deduped = append(deduped, tf)
+        }
+        if len(removed) > 0 {
+            logging.JSON("INFO", map[string]interface{}{"event": "fields_deduplicated_exact", "removed": removed, "reason": "移除完全重复的字段"})
+        }
+        filtered = deduped
+    }
+    // 主表和副表相同字段去重：以主表为主，移除副表的重复字段
+    if ds == "ymt" && (main == "order" || main == "order_info") {
+        mainTableFields := make(map[string]bool)
+        // 先收集主表的所有字段名
+        for _, tf := range filtered {
+            parts := strings.Split(tf, ".")
+            if len(parts) == 2 && parts[0] == "order" {
+                mainTableFields[parts[1]] = true
+            }
+        }
+        if len(mainTableFields) > 0 {
+            deduped := make([]string, 0, len(filtered))
+            removed := []string{}
+            for _, tf := range filtered {
+                parts := strings.Split(tf, ".")
+                if len(parts) == 2 {
+                    if parts[0] == "order" {
+                        // 主表字段，保留
+                        deduped = append(deduped, tf)
+                    } else {
+                        // 副表字段，检查是否与主表字段重复
+                        if mainTableFields[parts[1]] {
+                            // 字段名重复，移除副表字段
+                            removed = append(removed, tf)
+                            continue
+                        }
+                        // 字段名不重复，保留
+                        deduped = append(deduped, tf)
+                    }
+                } else {
+                    // 格式不正确，保留原样
+                    deduped = append(deduped, tf)
+                }
+            }
+            if len(removed) > 0 {
+                logging.JSON("INFO", map[string]interface{}{"event": "fields_deduplicated", "removed": removed, "reason": "主表和副表存在相同字段，以主表为主"})
+            }
+            filtered = deduped
+        }
+    }
     // 字段匹配校验（数量与顺序）
     if len(filtered) != len(fs) {
         logging.JSON("ERROR", map[string]interface{}{"event": "field_count_mismatch", "template_count": len(fs), "final_count": len(filtered)})
@@ -280,6 +338,7 @@ func (a *ExportsAPI) create(w http.ResponseWriter, r *http.Request) {
 			hdrs[i] = tf
 		}
 	}
+	// 列头去重：如果仍有重复的列头（中文标签），对非主表字段添加前缀
 	{
 		cnt := map[string]int{}
 		for _, h := range hdrs {
@@ -1027,10 +1086,28 @@ func toString(v interface{}) string {
 		return t
 	case int64:
 		return strconv.FormatInt(t, 10)
+	case int32:
+		return strconv.FormatInt(int64(t), 10)
 	case int:
 		return strconv.Itoa(t)
+	case uint64:
+		return strconv.FormatUint(t, 10)
+	case uint32:
+		return strconv.FormatUint(uint64(t), 10)
+	case uint:
+		return strconv.FormatUint(uint64(t), 10)
 	case float64:
+		// 对于整数部分，使用整数格式；对于小数部分，保留必要精度
+		if t == float64(int64(t)) {
+			return strconv.FormatInt(int64(t), 10)
+		}
 		return strconv.FormatFloat(t, 'f', -1, 64)
+	case float32:
+		// 对于整数部分，使用整数格式；对于小数部分，保留必要精度
+		if t == float32(int64(t)) {
+			return strconv.FormatInt(int64(t), 10)
+		}
+		return strconv.FormatFloat(float64(t), 'f', -1, 32)
 	case bool:
 		if t {
 			return "1"
@@ -1038,8 +1115,14 @@ func toString(v interface{}) string {
 		return "0"
 	case time.Time:
 		return t.Format("2006-01-02 15:04:05")
+	case nil:
+		return ""
 	default:
-		return fmt.Sprintf("%v", t)
+		// 尝试转换为字符串，如果是数字类型则格式化
+		if s := fmt.Sprintf("%v", t); s != "" {
+			return s
+		}
+		return ""
 	}
 }
 func renderSQL(q string, args []interface{}) string {

server/internal/exporter/sqlbuilder.go

@@ -516,12 +516,32 @@ func toString(v interface{}) string {
 		return t
 	case int64:
 		return strconv.FormatInt(t, 10)
+	case int32:
+		return strconv.FormatInt(int64(t), 10)
 	case int:
 		return strconv.Itoa(t)
+	case uint64:
+		return strconv.FormatUint(t, 10)
+	case uint32:
+		return strconv.FormatUint(uint64(t), 10)
+	case uint:
+		return strconv.FormatUint(uint64(t), 10)
 	case float64:
+		// 对于整数部分，使用整数格式；对于小数部分，保留必要精度
+		if t == float64(int64(t)) {
+			return strconv.FormatInt(int64(t), 10)
+		}
 		return strconv.FormatFloat(t, 'f', -1, 64)
+	case float32:
+		// 对于整数部分，使用整数格式；对于小数部分，保留必要精度
+		if t == float32(int64(t)) {
+			return strconv.FormatInt(int64(t), 10)
+		}
+		return strconv.FormatFloat(float64(t), 'f', -1, 32)
 	case time.Time:
 		return t.Format("2006-01-02 15:04:05")
+	case nil:
+		return ""
 	default:
 		return ""
 	}