我的API端点未返回预期的输出

Question

I have written a backend app with Express JS to retrieve info from a database through GET requests from an API endpoint. The query that I have used to GET from API endpoint is working in the Database , but I could not fetch the same details in a Web Browser as Response using Express JS. Tried my best to find out the issue, but I couldn't.

I tried to check whether I had a problem with my query, but the query is fetching the correct details, but I couldn't get any response in the web browser.

Here is my code where I think I had a bug :

      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]);
    });

SQL Query used to Fetch Details:

    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;

Error Log:

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

Try With Callback function.

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

parameter substitution Example

     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

I suspect using $1% is causing issues in your sql statement. Try the following instead.

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]);