public class FixMasterVisible {
  public static void main(String[] a) throws Exception {
    Class.forName("com.mysql.cj.jdbc.Driver");
    java.sql.Connection c = java.sql.DriverManager.getConnection(
      "jdbc:mysql://cq-cdb-8fjmemkb.sql.tencentcdb.com:27220/ylrz_saas?allowMultiQueries=true","root","Ylrz_1q2w3e4r5t6y");
    java.sql.Statement s = c.createStatement();
    java.sql.ResultSet r = s.executeQuery("SELECT COUNT(*) FROM information_schema.COLUMNS WHERE TABLE_SCHEMA=DATABASE() AND TABLE_NAME='company_workflow_lobster' AND COLUMN_NAME='visible_company_ids'");
    r.next();
    if (r.getInt(1)>0) { System.out.println("master already has column"); }
    else {
      s.execute("ALTER TABLE company_workflow_lobster ADD COLUMN visible_company_ids VARCHAR(500) DEFAULT NULL AFTER company_id");
      System.out.println("master column added");
    }
    c.close();
  }
}