如何编写SQL来检查MySQL 5.5中两列是否具有相同的值？

Question

需要检查的列

我需要检查此表中的两列是否匹配，或者是否与导出到txt文件不匹配

Answer 1

只需使用SELECT进行简单的WHERE查询，例如：

SELECT *
FROM table
WHERE idexx_patient_id = external_patient_id;

Answer 2

这会将问题中两列不匹配的所有行导出到文本文件

  var Client = Simperium.Client
  var Auth = Simperium.Auth

  var client = new Client( process.env.SIMPERIUM_APP_ID );

  var auth = new Auth( process.env.SIMPERIUM_APP_ID, process.env.SIMPERIUM_API_KEY );

  var interval = Number.POSITIVE_INFINITY, lastInt;

  client.connect();

  auth.on( 'authorize', function( user ) {
    var notes = client.bucket( 'note' );

    client.accessToken = user.access_token;
  } );

  auth.authorize(
    process.env.SIMPERIUM_EMAIL,
    process.env.SIMPERIUM_PASSWORD
  )