mysql为每一列添加“prefix”

Question

I need to add a 'prefix' in front of every value in a certain column.

Example: all fields in column x are: 200, 201, 202, 203, etc. I need them to be pn_200, pn_201, pn_202, pn_203, etc.

Is there a way to use ALTER or MODIFY commands to do this?

I would like something like ADD to BEGINNING of * column_name 'pn_'

Or perhaps a way to do it in PHP ? Maybe get the value of the field, turn that into a variable, and do something like.

`$variablex = `'SELECT column_name FROM table'
$result = mysqli_query($con, variablex);
 foreach($r=mysqli_fetch_row($result) {
    `ADD TO BEGINNING OF * column_name 'pn_'`

Is there anyway to do that?

Answer 1

Actually it's even easier.

UPDATE table SET column_name = CONCAT('pn_', column_name)

Without a WHERE clause it will update all the rows of your table

Answer 2

SELECT concat('pn_', column_name) AS column_name
FROM yourtable

but why do this at the database layer? It's trivial to do it in PHP:

SELECT column_name ...

while($row = mysql_fetch_assoc($result)) {
   $data = 'pn_' . $row['column_name'];
}

Answer 3

i think this is what you want

$que = "SELECT column_name FROM table";
$res = mysql_query($que, $con);
if(mysql_num_rows($res)>0){
while($row = mysql_fetch_array($res)){  

echo "PN_". $row['column_name'];

}
}

if you only want to show it wit pn_ at the beginnning but if you want to change it also in the database you need to select all get the id value and update it with concatination

Answer 4

UPDATE MyTable
SET MyField = CONCAT('pn_', MyField)