$user_id = '2';
In my database having one column with values like '2,3,5'. I just need to check whether the $user_id value is that column. Is there any easy way to check it?
As #Devsi Odedra, you can use find_in_set as:
SELECT *FROM table_name WHERE FIND_IN_SET($user_id,user_id) <> 0
Please read about find_in_set
Or you can also use like Operator as:
SELECT *FROM table_name WHERE CONCAT(",",user_id, ",") LIKE '%,$user_id,%';
Related
How is it possible to select the first column in the Where clause. I am trying to make a php function to retrieve table data based on the id, yet since the titles of the id columns are different in various tables, I need to refer to the first column in the Where clause as the first column is always the id column.
The scenario would be something like the following, but it throws errors and says that there is an error in the SQL syntax.
$stmt = $this->conn->prepare("SELECT * FROM $table WHERE column(1) = :id");
Thanks in advance.
I don't think there's a built-in way to do this. But you can query INFORMATION_SCHEMA.COLUMNS to get the column names.
$col_stmt = $this->conn->prepare("
SELECT column_name
FROM information_schema.columns
WHERE table_schema = DATABASE()
AND ordinal_position = 1
AND table_name = :table");
$col_stmt->execute([':table' => $table]);
$first_col = $col_stmt->fetchColumn();
$stmt = $this->conn->prepare("SELECT * FROM `$table` WHERE `$first_col` = :id");
Since there is no built-in way to do this, I came up with the following code block to get the first column and then use it in my SELECT statements.
$stmt = $this->conn->query("SHOW columns FROM $table");
return $stmt->fetch(PDO::FETCH_LAZY)[0];
I think this strategy is a bit shorter than Barmar's, though his is completely right and to the point.
I have table with 10 columns and I want to check input value in where clause of the MySQL query.
I want to do something like this. But, when I use this query I am getting an error.
for example :
SELECT * FROM user_data
where poll_title='$poll_title'
and '$voter' IN (user_vote_1,user_vote_2,user_vote_3...user_vote_10)
order by idpoll ASC
user_vote_1 to 10 (value is null'ed in the database) and I want to retrieve only that rows from a column which have $voter value.
I think you need this comparison (Not Sure OfCourse) :-
SELECT * FROM user_data
where poll_title = "$poll_title"
and (user_vote_1 = "$voter"
OR user_vote_2 = "$voter"
OR user_vote_3 = "$voter"
OR user_vote_4 = "$voter"......OR user_vote_10 = "$voter")
order by idpoll ASC
If I've understood what you want to do - return only the column with the value - then would coalesce do the job? This assumes that the value in user_vote_n will either match the value you're looking for or be null, since coalesce returns the first non-null argument.
(untested)
select coalesce(user_vote_1, user_vote_2, user_vote_3, ) as UserVote from user_data
where coalesce(user_vote_1, user_vote_2, user_vote_3, ) = '$voter';
That aside, this looks like a structure that could do with normalising - a single 'user_vote' column and a single 'user_vote_number' column.
I am trying to do a query in PHP PDO where it will grab a simple result. So like in my query I need it to find the row where the column group is 'Admin' and show what ever is in the group column. I know that we already know what it should be [Should be admin] but just need to get the query to work. Its only grabbing 1 row from my table, so will I need forsearch?
If I change WHERE group = 'Admin' to WHERE id = '1' it works fine. But I need it so it can be where group = 'admin'
$sql2 = "SELECT * FROM groups WHERE group = 'Admin'";
$stm2 = $dbh->prepare($sql2);
$stm2->execute();
$users2 = $stm2->fetchAll();
foreach ($users2 as $row2) {
print ' '. $row2["group"] .' ';
}
Thanks
group is a reserved word in MySQL, that's why it's not working. In general it's a bad idea to use reserved words for your column and table names.
Try using backticks around group in your query to get around this, so:
$sql2 = "SELECT * FROM groups WHERE `group` = 'Admin'";
Also you should really use placeholders for values, because you're already using prepared statement it's a small change.
Edit: just to clarify my last remark about the placeholders. I mean something like this:
$sql2 = "SELECT * FROM groups WHERE `group` = ?";
$stm2->execute(array('Admin'));
try to use wildcard in your WHERE Clause:
$sql2 = "SELECT * FROM groups WHERE group LIKE '%Admin%'";
Since the value in your table is not really Admin but Administrator then using LIKE and wildcard would search the records which contains admin.
If I have a database with a field called items with '1,2,3,7,15,25,64,346' in it.
Is there a function to use the commas as a separator and take each number and start a new query and get info for that id? Like a foreach but in sql?
I can see it so clear but cannot put it in words...
You can use this query,
SELECT * FROM TABLE_NAME WHERE COLUMN_NAME in (1,2,3,7,15,25,64,346);
Yes, there is. You can use command IN
mysql_query( 'SELECT * FROM `table` WHERE `id` IN ( 1,2,3,4,5 );' );
WHERE - IN
$row = '1,2,3,7,15,25,64,346'; // $row = $field['value']
$arr = explode(',',$row);
foreach($arr as $a) {
// write your query
}
You can use the query SELECT * FROM table_name WHERE id IN ( 1,2,3,4,5 ) to find data having id's.
No need to separate the values. This will give you the desired result.
There is so way to do a "SQL foreach". Do it using PhP
Also, having such fields means your database is not normalized. You should give a look at relational database normalization, otherwise the bigger your database will be, the bigger your problems will be.
It seems you want data like this where 'source' is table having the column
SELECT target.* FROM target
LEFT JOIN source ON FIND_IN_SET(target.id, source.ids_row)
I need to fetch a particular column value of a particular row using php in mysql.
For example if I want to fetch column2 value in row2, I tried using:
$qry = mysql_query("SELECT * from $table");
$data = mysql_fetch_row($qry);
$result = $data[1];
but this always returns only the first row value.
SELECT Column2
FROM $table
ORDER BY Something
LIMIT 1,1;
Or, if you know the key of the row
SELECT Column2
FROM $table
WHERE Key = Something
-- Optional: if you want 2nd after filtering
-- ORDER BY Something
-- LIMIT 1,1;
select COLUMNNAME from TABLENAME where ROWELEMENT="SOME_VALUE";
This should be your sql query..
You will need to access the value of that element using
$result['COLUMNNAME']
Complete code should look like this.
$query="select COLUMNNAME from TABLENAME where ROWELEMENT='SOME_VALUE'";
$result=mysql_query($query);
$result=mysql_fetch_array($result);
$columnvalue=$result['COLUMNNAME'];
Its bcoz mysql_query returns the result in an associative array form.
After the above code, You can access all elements like this.
$columnname[$index];
This will return the first value,
According to your question, You will need to first get the column values in a saperate array, and then access it using your index value..