I need a PHP function that deletes duplicate rows from MySQL database table. For example, I have a table like this:
I tried the following without success:
$find = mysql_query("SELECT * FROM users");
while ($row = mysql_fetch_assoc($find))
{
$find_1 = mysql_query("SELECT * FROM users ");
if (mysql_num_rows($find_1) > 0) {
mysql_query("DELETE FROM users WHERE ID =$row[num]");
}
I need to delete this duplicate rows and Keep only one of them only using PHP (and not my SQL database). Is there a way to do this?
You can do this with a single query, without a php loop (which, obviously, does not do what you want here):
delete t
from mytable t
inner join (select user, min(num) num from mytable group by user) t1
on t.user = t1.user and t.num > t1.num
This deletes rows that have the same user, while retaining the row with the smallest num.
Related
i have a small problem. I use two mysql queries for getting data.
First i want to get IDs from groups
$sqlGoups = "SELECT * from `groups` WHERE `Date`='$TodayDate' ";
$result = $conn->query($sqlGoups);
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
$IDgroups = $row["ID"];
With that, I'll get those IDs, for example 5, 7, 12, 15, 22
I want to put them all in the next mysql query:
$sqlNext = "SELECT * FROM `orders` WHERE ID = '$IDgroups' ORDER BY `ID` ASC ";
$result = $conn->query($sqlNext);
When I do this, I get the result only for the first ID (5). And I want for each
I can not INNER JOIN tables because I use this in next query.
I tried with foreach loop, but no effect.
Try this code
SELECT * FROM `orders`
WHERE ID REGEXP CONCAT('(^|,)(', REPLACE('$IDgroups', ',', '|'), ')(,|$)')
ORDER BY `ID` ASC
Just like #Elanochecer commented the best bet should be a JOIN statement, but if you wish to go through your route, you could use the IN and provide the IDs as comma separated string, your query should look similar to the one below:
...
$sqlNext = "SELECT * FROM orders WHERE ID IN ('$IDgroups') ORDER BY ID ASC ";
...
Also, confirm if $IDgroups is in the format 1,2,3,4
If you provide the schema I could come up with a workable JOIN statement for you, preferably you can create a repo with the schema
I am creating a Log in and I have separate tables for Users A and Users B.
What I want to do is check first in first table if the Users that trying to Login is in the Table A,
if YES, it will not go to the Table B to check the Login credentials, if NOT, go to Table B and check the Login credentials.
Table A
SELECT * FROM tableA WHERE userId='$userId' AND password='$password'
Table B
SELECT * FROM tableB WHERE accountNumber='$accountNumber' AND password='$password'
Note: The 2 Tables has different Field Name userId and accountNumber.
I presume you are fetching the values of username and password from client side so I will tell you only what you asked for.
$getUserBasic1=$db->prepare('SELECT * FROM tableA WHERE userId="$userId" AND password="$password"');
$getUserBasic1->execute();
$user= $getUserBasic1->fetchAll();
if(count($user)>0)
{
//if yes do what you want here
}
else
{
$getUserBasic2=$db2->prepare('SELECT * FROM tableB WHERE accountNumber="$accountNumber" AND password="$password"');
$getUserBasic2->execute();
$user2= $getUserBasic2->fetchAll();
//write your code here
}
You could use an INNER JOIN and select both table results taking Table A's result first if it exists, else take Table B's result.
Assuming both tables have some sort of reference like the User ID you can use something like this:
SELECT tbla.*, tblb.* FROM tableA tbla
INNER JOIN tableB tblb ON tbla.userId = tblb.userId
WHERE userId='$userId' OR accountNumber='$accountNumber' AND password='$password'
ORDER BY userId ASC
LIMIT 1
The query above uses the cross-reference (userId in this case) and joins both tables together before querying the results. It orders the results by Table A before Table B but limits the result to 1 bringing either Table A or Table B out depending which is null.
Try combining the tables, some thing like:
SELECT * FROM tableA, tableB WHERE tableA.userId='$userId' AND tableA.password='$password' OR tableB.accountNumber='$accountNumber' AND tableB.password='$password'
I have not checked, so may not work, but see if this gets what you are looking for!
Something like this:
$sql = "SQL QUERY FOR TABLEA";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// checking if result in TABLE A
}
else{
//search in TABLE B by updating your sql value.
}
I hope that you want to check for the registered user, the best way to do that is to keep one table and just search there itself keeping the userID as the primary key.
I'm developing a website using HTML, PHP and MySQL to access a database. On one page I present a table with data from that database. This is some of the code I'm using:
$sql1 = "SELECT * FROM MyTable ORDER BY ID ASC";
$rs1 = mysqli_query($link,$sql1);
(...)
while($row1 = mysqli_fetch_assoc($rs1)) {
echo "<tr><td>".$row1['ID']."</td><td>".$row1['Field1']."</td><td></td><td>".$row1['Field2']."</td><td>".$row1['Field3']."</td></tr>\n" ;
}
Notice the empty <td></td>? That's because I want to have there the number of time a given ID appears on two other tables (there are foreign keys involved, obviously). I have sorted out the code I need for that:
$sql2 = "SELECT (SELECT COUNT(*) FROM MyTable2 WHERE ID2=$row1['ID'])+(SELECT COUNT(*) FROM MyTable3 WHERE ID2=$row1['ID']) AS total";
However, I'm struggling with figuring out a way to add this result to the other table. Any help?
try with this.. it inserts the total to an table after selecting the count.
"INSERT INTO total_table (total)
SELECT (SELECT COUNT(*) FROM MyTable2 WHERE ID2=$row1['ID'])+(SELECT COUNT(*) FROM MyTable3 WHERE ID2=$row1['ID']) AS total
WHERE cid = 2"
I have a mysql query:
$query5 = mysql_query("SELECT * FROM `pages` WHERE (`id`='$switch' AND `rand`='$randID' AND `email`!='".$_SESSION['user']."') ");
And second:
$query5 = mysql_query("SELECT * FROM `pages_admin` WHERE (`pId`='$switch' AND `rand`='$randID' AND `admin`!='".$_SESSION['user']."') ");
I use a while loop to present data.
while($row = mysql_fetch_array($query5)) {}
I need one mysql query instead two.
If these tables are related you can JOIN them using the foreign key.
If I'm not mistaken this pId in the table pages_admin is a foreign key to the id on the table pages, is that correct?
If so, you could do something like this to you query:
"SELECT * FROM pages p
LEFT JOIN admin_pages ap on p.id = ap.pId
WHERE (`pId`=$switch AND `rand`=$randID AND `admin`!='{$_SESSION['user']}')"
Note that I've changed the syntax, instead of merging string you can use only one containing all variables you need.
I want to echo data from two tables to one variable. Here is the code that I have so far:
$sqlCommand = "SELECT * FROM News ORDER BY id DESC LIMIT 10";
$sqlCommand3 = "SELECT * FROM Users ORDER BY id";
$query = mysql_query($sqlCommand) or die(mysql_error());
$query3 = mysql_query($sqlCommand3) or die(mysql_error());
$count = mysql_num_rows($query);
if($count > 1) {
$News .= "";
// How do I add the query3 here?? along side the already existing one
while($row = mysql_fetch_array($query)) {
// some of the $row here are from query one and some are from query 3
$News .= "<div class=\"news-post\"> <img src=\"".$row['author']."\"><p>".$row['author']."</p> <h2>".$row['title']."</h2></div>";
} // close while
This isn't the right way to go about it, instead try using a SQL join. In this case, you'll want a unique FULL OUTER JOIN.
SELECT * FROM News
FULL OUTER JOIN USERS
ON News.id = Users.id
WHERE News.id IS NULL
OR Users.id IS NULL;
This should give you all rows containing all columns from both tables. Depending on the actual relationship, you may want some different kind of join (refer to previous link)..but this seems like what you were trying to accomplish in your example.
Warning: you are using the mysql_* extension which has been deprecated in PHP 5.5. Please use either mysqli_* or PDO.
Your User table should be linked to the News table by a oneToMany association.
So a user writes a news and a new is written by a user.
And you need to add a join in your SQL query.
$sql = 'SELECT u.username, n.* FROM News n JOIN User u ON n.user_id = u.id';
Then, you while only have to execute one SQL statement and display the result in you HTML.
Have look to this website.