我的API端點未返回預期的輸出

Question

我已經使用Express JS編寫了一個后端應用程序，以通過API端點的GET請求從數據庫中檢索信息。 我曾經從API端點獲取的查詢正在數據庫中運行，但是我無法在Web瀏覽器中獲取與使用Express JS的響應相同的詳細信息。 盡力找出問題所在，但我做不到。

我試圖檢查我的查詢是否有問題，但是查詢獲取的是正確的詳細信息，但是我無法在Web瀏覽器中得到任何響應。

這是我認為存在錯誤的代碼：

      const { rows } = await pool.query(
                'SELECT  branches.ifsc, branches.bank_id, branches.branch, branches.address, branches.city, branches.district, branches.state FROM branches WHERE branches.branch LIKE $1% LIMIT $2 OFFSET $3' ,

        [q, limit, offset]
      );

      res.send(rows[0]);
    });

用於獲取詳細信息的SQL查詢：

    SELECT branches.ifsc, branches.bank_id, branches.branch, branches.address, branches.city, branches.district, branches.state FROM branches WHERE branches.branch LIKE '%RTGS%' ORDER BY branches.ifsc LIMIT 3;

錯誤日志：

Server is running on 7000
(node:19484) UnhandledPromiseRejectionWarning: error: syntax error at or near "LIMIT"
    at Connection.parseE (/home/kiddo/Desktop/backend/node_modules/pg/lib/connection.js:604:11)
    at Connection.parseMessage (/home/kiddo/Desktop/backend/node_modules/pg/lib/connection.js:401:19)
    at Socket.<anonymous> (/home/kiddo/Desktop/backend/node_modules/pg/lib/connection.js:121:22)
    at Socket.emit (events.js:200:13)
    at addChunk (_stream_readable.js:294:12)
    at readableAddChunk (_stream_readable.js:275:11)
    at Socket.Readable.push (_stream_readable.js:210:10)
    at TCP.onStreamRead (internal/stream_base_commons.js:166:17)
(node:19484) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:19484) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Answer 1

嘗試使用回調功能。

con.query("YOUR SQL QUERY HERE", function (err, result, fields) {
    if (err) throw err;
    console.log(result);
  });

參數替換示例

     var sql = "SELECT * FROM table WHERE field1 = ? AND field2 >= ?";
connection.query(sql, [value1, value2], function(err, result, fields) {
    //do your operations HERE
    console.log(result);

});

Answer 2

我懷疑使用$1%會導致您的sql語句出現問題。 請嘗試以下方法。

const { rows } = await pool.query(
        'SELECT  branches.ifsc, branches.bank_id, branches.branch, branches.address, branches.city, branches.district, branches.state FROM branches WHERE branches.branch LIKE $1 LIMIT $2 OFFSET $3' ,
['%'+q+'%', limit, offset]);