Question

Sorry, guys.I am quite new in mysql but I do need help from getting and merging data from 2 tables.

table_a

ID | TITLE | CONTENT | DATE

table_b

ID | POST_ID | IMAGE

Here’s my code

$query = "SELECT table_a.*, table_b.IMAGE FROM table_a
LEFT JOIN table_b
      ON table_a.ID = table_b.POST_ID
      ORDER BY table_a.DATE";
$mysql_result = mysql_query($query);

$result = array();
while ($row = mysql_fetch_assoc($mysql_result)) {
   $result[] = $row;
}
print json_encode($result);

However, for those record in table_a which got more than 1 IMAGE, my json contain duplicated CONTENT with different IMAGES.

Is there any methods to merge IMAGE with the same ID into a single record?

Thanks for any helps!

Answer 1

If I understand correctly, you want to have all fields from table_a, and only one (maybe combined) field from table_b.

First of all, you have to decide what you want to get, if you have more than one image:

• Only 1 image? Use MIN(table_b.IMAGE) or MAX(table_b.IMAGE) in the
  following SQL
• All images separated by e.g. a comma? Use GROUP_CONCAT(table_b.IMAGE SEPARATOR ',') or similar in the following SQL

Next you have to understand, that to get only one row per table_a.ID, you have to group by table_a.ID, so we have

SELECT
  table_a.*,
  <function from above> AS image
FROM  table_a
LEFT JOIN table_b
      ON table_a.ID = table_b.POST_ID
GROUP BY table_a.ID
ORDER BY table_a.DATE