Hi, This thing puzzles me for quite some time and I wasn't successful in finding a clear answer anywhere - I would be grateful for some help.
Here is a db example: table_1 id some_field_01 [...] some_field_20 table_2 itemid (table_1_id) value Let's say that the table_2 is used to store some properties of the item in table_1, there can be many of them (let's say these are just integers values - not that important in this example). What I'd like to get is the item from table_1 and the item properties from table_2, I can do 2 things: 1: on table_1 SELECT * FROM table_1 WHERE id = SOME_ID then on table_2 SELECT value FROM table_1 WHERE itemid = SOME_ID.from.table_1 so I get one row from table_1 and many rows from table_2 2: on both tables: SELECT tb_1.*,tb_2.value AS property FROM table_1 AS tb_1, table_2 AS tb_2 WHERE tb_1.id = SOME_ID AND tb_1.id = tb_2.itemid so I get many rows with one query. The question is, which way is better if these requests may be executed a large number of times? I think 1 query is better than 2 but if the table_1 holds a lot of data - resending the whole thing every time (example 2) just to get the one integer value seems like a waste of resources. Or is there a better way to do it? Could someone enlighten me? Thanks! -- Regards, Lecho -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
