在MySQL中删除第一行并将元素添加到最后一行

Question

I have a table called message_pool and it only has one attribute called message . For example:

hello 1
hello 2
hello 3

I want to delete first row and add myValue to last row . I have basically two queries.

$query_one = "DELETE FROM message_pool LIMIT 1";
$query_two = "INSERT INTO message_pool VALUES ('$myValue');"

If I only run $query_one this result happens:

hello 2
hello 3

If I only run $query_two this result happens:

hello 1
hello 2
hello 3
myValue

ODLY! If I first run $query_one then $query_two this result happens:

myValue
hello 2
hello 3

But I want this result to get.

hello 2
hello 3
myValue

How come it places myValue to the first row, but when I run the second query standalone it places myValue to last row?

Answer 1

Just add a primary key to your table and set it to autoincrement. It is a good practice to have primary key in every table.

ALTER TABLE `message_pool` ADD `id` INT NOT NULL AUTO_INCREMENT FIRST, ADD PRIMARY KEY (`id`);

Your above query work fine after you execute above code.