feat: 新增all选项

db.go

@@ -79,8 +79,13 @@ func GetSensorData(sensorID int, limit int, startDate time.Time, endDate time.Ti
 		args = append(args, endDate)
 	}
 
-	query += " ORDER BY timestamp DESC LIMIT ?"
+	query += " ORDER BY timestamp DESC"
+
+	// 只有当limit > 0时才添加LIMIT子句
+	if limit > 0 {
+		query += " LIMIT ?"
 		args = append(args, limit)
+	}
 
 	rows, err := db.Query(query, args...)
 	if err != nil {
@@ -128,8 +133,13 @@ func GetAllSensorData(limit int, startDate time.Time, endDate time.Time) ([]Sens
 		args = append(args, endDate)
 	}
 
-	query += " ORDER BY timestamp DESC LIMIT ?"
+	query += " ORDER BY timestamp DESC"
+
+	// 只有当limit > 0时才添加LIMIT子句
+	if limit > 0 {
+		query += " LIMIT ?"
 		args = append(args, limit)
+	}
 
 	rows, err := db.Query(query, args...)
 	if err != nil {

http_server.go

@@ -81,7 +81,7 @@ func handleGetData(w http.ResponseWriter, r *http.Request) {
 	if limitStr != "" {
 		if limitStr == "all" {
 			noLimit = true
-			limit = 1000000 // 使用一个非常大的数值作为实际上的"无限制"
+			limit = 0 // 设置为0表示不使用LIMIT子句
 		} else {
 			limit, err = strconv.Atoi(limitStr)
 			if err != nil || limit <= 0 {

templates/index.html

@@ -159,6 +159,7 @@
                     <option value="1000">1000</option>
                     <option value="2000">2000</option>
                     <option value="5000">5000</option>
+                    <option value="50000">50000</option>
                     <option value="all">全部</option>
                 </select>
             </div>