用来自另一个表的数据更新表

Question

I have two tables one tbl_demographics with coluimns [staffid, natid] and another tbl_nationality with columns [natid, description].

HR sends me staff data in excel with the staffid and nationality which I upload as it is. Only problem is the nationality column contains data such as Canadian instead of (CAN) or Nigerian instead of (NGA).

How do i write a script in sql (or php even) that can update all the natid in tbl_demographics into data that is corresponding the correct natid in tbl_nationality? I'm using mysql server (and php if necessary).

The data they send:

staffid | natid

201001  | Canadian

202332  | Nigerian

Expected tables look:

staffid | natid (tbl_demographics)

201001  | CAN
202332  | NGA


natid   | description (tbl_nationality)

CAN     | Canada
NGA     | Nigeria

Answer 1

Create a map where key is full name of country and value is abreviation. for country field, if key is in map use the value as country else use the key/entry from hr

Answer 2

simply:

$count = 0;
$result = mysql_query("SELECT * FROM tbl_nationality");
while ($source = mysql_fetch_array($result)) {
  $nationality[$count] = $source['description'];
  $natid[$count] = $source['natid'];
  $count++;
}

$num = 0;
$result = mysql_query("SELECT * FROM tbl_demographics");
while ($source = mysql_fetch_array($result)) {
  $count = 0;
  while (isset($natid[$count])) {
    if ($source['natid'] == $nationality[$count]) {
      $index[$num] = $source['staffid'];
      $correctid[$num] = $natid[$count];
      $num++;
    }
    $count++;
  }
}
$num = 0;
while (isset($index[$num])) {
  mysql_query("UPDATE tbl_demographics SET `natid` = '$correctid[$num]' WHERE `staffid` = '$index[$num]'");
  $num++;
}

which should then select the variables that are incorrect and correct them.

Answer 3

Use this, assuming you place the HR excel data in a table called tbl_excel (only SQL):

UPDATE tbl_demographics d, tbl_nationality n, tbl_excel e
SET d.nat_id = n.natid
WHERE n.description = e.description
  AND e.staffid = d.staffid

This of course needs the descriptions of the data they send (Canada, Canadian) match the descriptions on the tbl_nationality table.

Answer 4

$query_demo = "SELECT * FROM tbl_demographics";
$res_demo = mysql_query($query_demo);
while ($row = $mysql_fetch_assoc($res_demo)) {
    $query_nat = "SELECT natid FROM tbl_nationality WHERE description='" . $row["description"] . "'";
    $res_nat = mysql_query($query_nat);
    $arr_nat = $mysql_fetch_assoc($res_nat);
    if ($arr_nat) {
        $query_update = "UPDATE tbl_demographics SET natid='" . $arr_nat["natid"] . "' WHERE staffid=" . $row["staffid"];
        mysql_query($query_update);
    }
}

EDIT: This assumes that tbl_demographics initially contains some wrong natids, and that the wrong natids correspond to descriptions found in tbl_nationality.

My code loops through the initial 'wrong' tbl_demographics, looks up the corresponding description in tbl_nationality, reads the natid from there, and updates the corresponding entry in tbl_demographics.