Mysql - how to UPDATE table from another table with several WHERE conditions

Question

I have 2 tables:

table1 which looks like:

column1 | column2 | item1 | item2 | item3 | item4 | (it goes till item50)

value | value | value | value | value | value | .........

table_to_update that looks like:

column1 | colum2 | item

value | value | value of item1

value | value | value of item2

value | value | value of item3

value | value | value of item4

value | value | value of item....

when I change in table1 the value of colum1 or column2 then I want these data changed in table_to_update. Note values of items 1-50 never change

So I can update value of item1 by using this PHP commands:

UPDATE table_to_update, table1
SET table_to_update.column1 = table1.column1, table_to_update.column2 = table1.column2
WHERE table_to_update.item = table1.item1

Then value of item2 with:

UPDATE table_to_update, table1
SET table_to_update.column1 = table1.column1, table_to_update.column2 = table1.column2
WHERE table_to_update.item = table1.item2

(all the same but table1.item1 is changed to table1.item2)

And do that 50 times which is obviously not very convenient

Is there a way to only have the WHERE part changed, such as something like this (which is wrong):

UPDATE table_to_update, table1
SET table_to_update.column1 = table1.column1, table_to_update.column2 = table1.column2
WHERE table_to_update.item = table1.item1 ("THEN") table_to_update.item = table1.item2 ("THEN") table_to_update.item = table1.item3 ....

Alternatively I can write commands like below for the 50 items:

UPDATE table_to_update, table1
SET table_to_update.column1 = table1.column1, table_to_update.column2 = table1.column2
WHERE table_to_update.item = table1.item1

UPDATE table_to_update, table1
SET table_to_update.column1 = table1.column1, table_to_update.column2 = table1.column2
WHERE table_to_update.item = table1.item2

but I don't know how to have them all run from 1 PHP page. It looks like I need to create 50 PHP pages with 1 statement each?

Answer 1

$data = mysql_fetch_assoc(mysql_query('SELECT * FROM table1'));

foreach ($data as $row) {

    mysql_query("UPDATE table_to_update SET column1 = '{$row['column1']}', column2 = '{$row['columnd2']}' WHERE item = '{$row['item1']}'");



}

I think thats where you need to be heading. But it needs more work and is not secure. If anyone wants to contribute go ahead.