MySQL insert a new row or update old one

Today I stumbled upon a newish MySQL feature that can often be very useful. Since MySQL 4.1 there’s a non-standard feature (i.e. it’s an extension of SQL standard and won’t work on other databases) that lets you insert a new row, but if it happens that a row with same primary/unique key already exists it [...]

MySQL: Get total number of rows when using LIMIT

Every now and then you need to limit the number of rows MySQL returns, i.e. use the LIMIT clause. Result set pagination is by far the most often usage of LIMIT clause, since you usually want to select only rows you’ll be displaying on certain page.
The problem is that for pagination you also need total [...]