PHP 连接表 mysql

Question

So I have two tables:

Table1 (sales)

• ID
• Ident
• Date
• Status

Table2 (users)

• ID
• Ident
• Fullname
• Email

This is how I query the value:

<?php      
       $query = "SELECT * FROM sales WHERE status='OK' ORDER BY STR_TO_DATE(`date`, '%Y/%m/%d %H:%i:%s') DESC LIMIT 5";
           if ($result = $link->query($query)) {
                  $num_rows = 0;
                  while ($row = $result->fetch_assoc()) {
                      $num_rows++;
    
                      echo '<div class="my-box">';
                      echo "{$row['id']}";
                      echo "{$row['date']}";
                      echo "{$row['dbirth']}";
                      echo "{$row['email']}";
                      echo "{$row['ident']}";
                      echo '</div>';
                  }
                  $result->free();
              }
          ?>

Right now, it echo the ident for the row, but insted of showing the ident, I was it to display the Fullname that has the ident from Table2. I tried something like SELECT * FROM sales LEFT JOIN users on sales.id = users.id , but that doesn't gives me the Fullname . Any tips?

Answer 1

Your SQL seems wrong.

When you join tables, do this way.

SELECT column_name(s) FROM table1 INNER JOIN table2 ON table1.column_name = table2.column_name;

If you join tables right, you will be able to retrieve the 'Fullname' column.

Answer 2

I believe the Ident field would be the primary key in the users table and foreign key in the sales table. If yes, this will return the desired result along with other listed fields from both tables.

SELECT sales.ID AS sales_ID,sales.Ident AS Identity,Date,Status,Fullname,Email FROM sales
INNER JOIN users ON sales.Ident = users.Ident
WHERE status='OK'
ORDER BY STR_TO_DATE(`date`, '%Y/%m/%d %H:%i:%s') 
DESC LIMIT 5

If the date field is updated to date or datetime, simply use

ORDER BY DATE

For Better Database practises:

1. You need to change the date field data type to either date or datetime
2. You need to have an understanding of the Primary and Foreign key concept in RDBMS.
3. You need to learn JOINS in SQL