Update multiple records with single query, or Bundle Record Update

Actually it's a lie, it's not a single query, it's 3 queries, but it's still much more sufficient if you deal with more than 3 records to be updated with different values.

So, the problem is to run lot of update queries like:

update table_name set value_column='value1' where key_column = key1;

update table_name set value_column='value2' where key_column = key2;

...

update table_name set value_column='valueN' where key_column = keyN;

If you have N more than 3, then you should test the performance of the following approach:

1. create temporary table temp_table(k int,v varchar);

2. insert int temp_tabl values

(key1,'value1'),

(key2,'value2'),

...,

(keyN,'valueN')

3. update table_name, temp_table set

table_name.value_column=temp_table.v

where table_name.key_column=temp_table.k

For ~50 records, it works ~2 times faster, so think about it.

Как-то-так