I'd like to get all of a mysql table's col names into an array in php?
Is there a query for this?
The best way is to use the INFORMATION_SCHEMA metadata virtual database. Specifically the INFORMATION_SCHEMA.COLUMNS table...
SELECT `COLUMN_NAME`
FROM `INFORMATION_SCHEMA`.`COLUMNS`
WHERE `TABLE_SCHEMA`='yourdatabasename'
AND `TABLE_NAME`='yourtablename';
It's VERY powerful, and can give you TONS of information without need to parse text (Such as column type, whether the column is nullable, max column size, character set, etc)...
Oh, and it's standard SQL (Whereas SHOW ... is a MySQL specific extension)...
For more information about the difference between SHOW... and using the INFORMATION_SCHEMA tables, check out the MySQL Documentation on INFORMATION_SCHEMA in general...
You can use the following query for MYSQL:
SHOW `columns` FROM `your-table`;
Below is the example code which shows How to implement above syntax in php to list the names of columns:
$sql = "SHOW COLUMNS FROM your-table";
$result = mysqli_query($conn,$sql);
while($row = mysqli_fetch_array($result)){
echo $row['Field']."<br>";
}
For Details about output of SHOW COLUMNS FROM TABLE visit: MySQL Refrence.
Seems there are 2 ways:
DESCRIBE `tablename`
or
SHOW COLUMNS FROM `tablename`
More on DESCRIBE here: http://dev.mysql.com/doc/refman/5.0/en/describe.html
I have done this in the past.
SELECT column_name
FROM information_schema.columns
WHERE table_name='insert table name here';
Edit: Today I learned the better way of doing this. Please see ircmaxell's answer.
Parse the output of SHOW COLUMNS FROM table;
Here's more about it here: http://dev.mysql.com/doc/refman/5.0/en/show-columns.html
Use mysql_fetch_field() to view all column data. See manual.
$query = 'select * from myfield';
$result = mysql_query($query);
$i = 0;
while ($i < mysql_num_fields($result))
{
$fld = mysql_fetch_field($result, $i);
$myarray[]=$fld->name;
$i = $i + 1;
}
"Warning
This extension is deprecated as of PHP 5.5.0, and will be removed in the future."
The simplest solution out of all Answers:
DESC `table name`
or
DESCRIBE `table name`
or
SHOW COLUMNS FROM `table name`
An old PHP function "mysql_list_fields()" is deprecated. So, today the best way to get names of fields is a query "SHOW COLUMNS FROM table_name [LIKE 'name']". So, here is a little example:
$fields = array();
$res=mysql_query("SHOW COLUMNS FROM mytable");
while ($x = mysql_fetch_assoc($res)){
$fields[] = $x['Field'];
}
foreach ($fields as $f) { echo "<br>Field name: ".$f; }
when you want to check your all table structure with some filed then use this code. In this query i select column_name,column_type and table_name for more details . I use order by column_type so i can see it easily.
SELECT `COLUMN_NAME`,COLUMN_TYPE,TABLE_NAME
FROM `INFORMATION_SCHEMA`.`COLUMNS`
WHERE `TABLE_SCHEMA`='yourdatabasename' order by DATA_TYPE;
If you want to check only double type filed then you can do it easily
SELECT `COLUMN_NAME`,COLUMN_TYPE,TABLE_NAME,DATA_TYPE
FROM `INFORMATION_SCHEMA`.`COLUMNS`
WHERE `TABLE_SCHEMA`='yourdatabasename' AND DATA_TYPE like '%bigint%' order by DATA_TYPE;
if you want to check which field allow null type etc then you can use this
SELECT `COLUMN_NAME`,COLUMN_TYPE,TABLE_NAME,IS_NULLABLE,DATA_TYPE
FROM `INFORMATION_SCHEMA`.`COLUMNS`
WHERE `TABLE_SCHEMA`='yourdatabasename' and DATA_TYPE like '%bigint%' and IS_NULLABLE ='NO' order by COLUMN_TYPE;
you want to check more then thik link also help you.
https://dev.mysql.com/doc/refman/5.7/en/columns-table.html
this generates a string of column names with a comma delimiter:
SELECT CONCAT('(',GROUP_CONCAT(`COLUMN_NAME`),')')
FROM `INFORMATION_SCHEMA`.`COLUMNS`
WHERE `TABLE_SCHEMA`='database_name'
AND `TABLE_NAME`='table_name';
function get_col_names(){
$sql = "SHOW COLUMNS FROM tableName";
$result = mysql_query($sql);
while($record = mysql_fetch_array($result)){
$fields[] = $record['0'];
}
foreach ($fields as $value){
echo 'column name is : '.$value.'-';
}
}
return get_col_names();
Not sure if this is what you were looking for, but this worked for me:
$query = query("DESC YourTable");
$col_names = array_column($query, 'Field');
That returns a simple array of the column names / variable names in your table or array as strings, which is what I needed to dynamically build MySQL queries. My frustration was that I simply don't know how to index arrays in PHP very well, so I wasn't sure what to do with the results from DESC or SHOW. Hope my answer is helpful to beginners like myself!
To check result: print_r($col_names);
SHOW COLUMNS in mysql 5.1 (not 5.5) uses a temporary disk table.
http://dev.mysql.com/doc/refman/5.1/en/internal-temporary-tables.html
http://dev.mysql.com/doc/refman/5.1/en/show-columns.html
So it can be considered slow for some cases. At least, it can bump up your created_tmp_disk_tables value. Imagine one temporary disk table per connection or per each page request.
SHOW COLUMNS is not really so slow, possibly because it uses file system cache. Phpmyadmin says ~0.5ms consistently. This is nothing compared to 500ms-1000ms of serving a wordpress page. But still, there are times it matters. There is a disk system involvement, you never know what happens when server is busy, cache is full, hdd is stalled etc.
Retrieving column names through SELECT * FROM ... LIMIT 1 was around ~0.1ms, and it can use query cache as well.
So here is my little optimized code to get column names from a table, without using show columns if possible:
function db_columns_ar($table)
{
//returns Array('col1name'=>'col1name','col2name'=>'col2name',...)
if(!$table) return Array();
if(!is_string($table)) return Array();
global $db_columns_ar_cache;
if(!empty($db_columns_ar_cache[$table]))
return $db_columns_ar_cache[$table];
//IMPORTANT show columns creates a temp disk table
$cols=Array();
$row=db_row_ar($q1="SELECT * FROM `$table` LIMIT 1");
if($row)
{
foreach($row as $name=>$val)
$cols[$name]=$name;
}
else
{
$coldata=db_rows($q2="SHOW COLUMNS FROM `$table`");
if($coldata)
foreach($coldata as $row)
$cols[$row->Field]=$row->Field;
}
$db_columns_ar_cache[$table]=$cols;
//debugexit($q1,$q2,$row,$coldata,$cols);
return $cols;
}
Notes:
As long as your tables first row does not contain megabyte range of data, it should work fine.
The function names db_rows and db_row_ar should be replaced with your specific database setup.
IN WORDPRESS:
global $wpdb; $table_name=$wpdb->prefix.'posts';
foreach ( $wpdb->get_col( "DESC " . $table_name, 0 ) as $column_name ) {
var_dump( $column_name );
}
Try this one out I personally use it:
SHOW COLUMNS FROM $table where field REGEXP 'stock_id|drug_name'
This question is old, but I got here looking for a way to find a given query its field names in a dynamic way (not necessarily only the fields of a table). And since people keep pointing this as the answer for that given task in other related questions, I'm sharing the way I found it can be done, using Gavin Simpson's tips:
//Function to generate a HTML table from a SQL query
function myTable($obConn,$sql)
{
$rsResult = mysqli_query($obConn, $sql) or die(mysqli_error($obConn));
if(mysqli_num_rows($rsResult)>0)
{
//We start with header. >>>Here we retrieve the field names<<<
echo "<table width=\"100%\" border=\"0\" cellspacing=\"2\" cellpadding=\"0\"><tr align=\"center\" bgcolor=\"#CCCCCC\">";
$i = 0;
while ($i < mysqli_num_fields($rsResult)){
$field = mysqli_fetch_field_direct($rsResult, $i);
$fieldName=$field->name;
echo "<td><strong>$fieldName</strong></td>";
$i = $i + 1;
}
echo "</tr>";
//>>>Field names retrieved<<<
//We dump info
$bolWhite=true;
while ($row = mysqli_fetch_assoc($rsResult)) {
echo $bolWhite ? "<tr bgcolor=\"#CCCCCC\">" : "<tr bgcolor=\"#FFF\">";
$bolWhite=!$bolWhite;
foreach($row as $data) {
echo "<td>$data</td>";
}
echo "</tr>";
}
echo "</table>";
}
}
This can be easily modded to insert the field names in an array.
Using a simple: $sql="SELECT * FROM myTable LIMIT 1" can give you the fields of any table, without needing to use SHOW COLUMNS or any extra php module, if needed (removing the data dump part).
Hopefully this helps someone else.
if you use php, use this gist.
it can get select fields full info with no result，and all custom fields such as:
SELECT a.name aname, b.name bname, b.*
FROM table1 a LEFT JOIN table2 b
ON a.id = b.pid;
if above sql return no data,will also get the field names aname, bname, b's other field name
just two line:
$query_info = mysqli_query($link, $data_source);
$fetch_fields_result = $query_info->fetch_fields();
This query fetches a list of all columns in a database without having to specify a table name. It returns a list of only column names:
SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_schema = 'db_name'
However, when I ran this query in phpmyadmin, it displayed a series of errors. Nonetheless, it worked. So use it with caution.
if you only need the field names and types (perhaps for easy copy-pasting into Excel):
SELECT COLUMN_NAME, DATA_TYPE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA='databasenamegoeshere'
AND DATA_TYPE='decimal' and TABLE_NAME = 'tablenamegoeshere'
remove
DATA_TYPE='decimal'
if you want all data types
i no expert, but this works for me..
$sql = "desc MyTable";
$result = #mysql_query($sql);
while($row = #mysql_fetch_array($result)){
echo $row[0]."<br>"; // returns the first column of array. in this case Field
// the below code will return a full array-> Field,Type,Null,Key,Default,Extra
// for ($c=0;$c<sizeof($row);$c++){echo #$row[$c]."<br>";}
}
I have tried this query in SQL Server and this worked for me :
SELECT name FROM sys.columns WHERE OBJECT_ID = OBJECT_ID('table_name')
The call of DESCRIBE is working fine to get all columns of a table but if you need to filter on it, you need to use the SHOW COLUMNS FROM instead.
Example of PHP function to get all info of a table :
// get table columns (or return false if table not found)
function get_table_columns($db, $table) {
global $pdo;
if($cols = $pdo->query("DESCRIBE `$db`.`$table`")) {
if($cols = $cols->fetchAll(PDO::FETCH_ASSOC)) {
return $cols;
}
}
return false;
}
In my case, I had to find the primary key of a table. So, I used :
SHOW COLUMNS FROM `table` WHERE `Key`='PRI';
Here is my PHP function :
// get table Primary Key
function get_table_pk($db, $table) {
global $pdo;
$q = "SHOW COLUMNS FROM `$db`.`$table` WHERE `Key` = 'PRI'";
if($cols = $pdo->query($q)) {
if($cols = $cols->fetchAll(PDO::FETCH_ASSOC)) {
return $cols[0];
}
}
return false;
}
I'm trying to create a function to count different table rows in my MySQL database. I have the following script, but when executing it, it will generate an error saying that the variable $con is not set, but it is. So my question is how can I use "global" in this statement?
function countrows($rows){
$sql = mysqli_query($con,"SELECT * FROM $rows");
$num_rows = mysqli_num_rows($sql);
echo $num_rows;
}
If $con is defined in the global scope (that is, it is not created inside any other functions), then make this call:
global $con;
as the first line in that function.
You might also pass it as a function parameter:
function countrows($rows, $con){
...
}
Here's how you do it:
function countrows($rows){
global $con;
$sql = mysqli_query($con,"SELECT * FROM $rows");
$num_rows = mysqli_num_rows($sql);
echo $num_rows;
}
BTW, if the table is large, I recommend using SELECT COUNT(*) instead of SELECT *. The latter requires downloading the entire contents of the table in order to count the rows, the former can usually be done efficiently in SQL.
This is my first code-question! I'm a beginner at both MySQL and PHP, so this might be really simple! Here is my code:
This is a file included in my Index.php...:
<?php
$query="SELECT * FROM wines WHERE Type='$type' AND Country='$country'";
$products=mysql_query($query);
?>
And these are the variables set with the $_GET function:
<?php
$type=$_GET['type'];
$fruit=$_GET['fruit'];
$country=$_GET['country'];
?>
And then later I'll fetch the array and work with it.
The problem is that my $query works fine with just the '$type'-variable, but not with the $country -variable - - - - or any other variable I've tried.
I use Microsoft Webmatrix and it tells me that the issue arises the very moment I type in the $-sign in the second variable...
So confused! Hope you can help a newcomer :)
EDIT: I found out the problem was with the "ticks" around my variables. The correct way to do it is with backticks ( `` ). Also, I started using PDO and MySQLi instead of mysql. For beginners, MySQLi is probably the easiest. Started sanitizing too.
Just a couple of (important) points to note...
You should probably be using the mysqli_* functions in the place of the mysql_ functions, as they are going to be deprecated in a following release.
start sanitizing your input before making DB queries. It's a good habit to get into early, and will save you a lot of headaches in the long run!
a good habit it to use sprintf and mysqli_real_escape_string to build your SQL before executing it on the db:
$sql = sprintf("SELECT * FROM wines WHERE Type='%s' AND Country='%s'" ,
mysqli_real_escape_string($db_object, $type),
mysqli_real_escape_string($db_object, $country));
$results = mysqli_query($db_object, $sql);
ps. in my example $db_object is coming from the call to mysqli_connect()
EDIT:
Using the (soon-to-be-defunct) mysql_ functions would be something like the following for the above example:
$sql = sprintf("SELECT * FROM wines WHERE Type='%s' AND Country='%s'" ,
mysql_real_escape_string($type),
mysql_real_escape_string($country));
$results = mysql_query($sql);
If you don't send a $type in your query string, the query is
SELECT * FROM wines WHERE Type='' AND [other stuff];
which will give back only wines with type = '';
Try:
<?php
$wheres=array();
if (isset($type)){$wheres['Type']=$type;}
if (isset($type)){$wheres['Country']=$country;}
// and so forth for each parameter
$query="SELECT * FROM wines";
if (count($wheres) != 0){
$query.=" WHERE ";
foreach ($wheres as $k => $v){$query.="$k='$v' AND ";}
$query.=" 1=1;"
}
$products=mysql_query($query);
?>
I'm new in mysql language and can not understand difference between procedures and functions, can anyone answer in which case should be use this routines ?
Also have some example => I've table named "data" and columns named "id"(primary key) , "local". this local includes multiple exactly same data. I want to search every id of this "data" (and after result manipulate with it) table which local equal to (for instance) 'something'
Please answer in this question ... Thanks
Functions:
select <function>(column) from table where <condition>;
Procedure:
call <procedure>( param0, param1 );
To get your result:
select * from <table> where data like "%something%";
I suppose that you use php with mysql.
your query should be
$result = mysql_query("SELECT * FROM data WHERE local='something'");
while($row = mysql_fetch_array($result))
{
// here you manipulate with your data
// for example:
echo $row['id'];
}
I'm trying this query:
//connect;
$site = mysql_real_escape_string($_GET['site']);
$data = mysql_query("SELECT * FROM Items WHERE Site = '$site'");
while($row = mysql_fetch_array( $data ))
{
print $row['type'];
}
doesn't print anything, running SELECT * FROM Items WHERE Site = 'http://rollingstone.com/' from PHPMyAdmin returns one row.
I'm sure it must be something really basic, since I haven't got much experience with MySQL.
I'm trying it here btw: http://www.chusmix.com/game/insert/get-items.php?site=http://rollingstone.com/
What am I doing wrong?
Make sure $site actually contains something; doing a quick echo $site before your mysql_query() should tell you this. If it's empty, try print_r($_GET) to see if it's in the $_GET array. It should be, but it might not for some other reason; check any code above this snippet for stuff that modifies $_GET or $_REQUEST in any way.
To request data from a MySQL table, you need to connect to the server using mysql_connect(), then select the database with mysql_select_db(). PHP should throw errors, but to be sure put these lines at the top of your script:
error_reporting(E_ALL);
ini_set('display_errors', '1');
All errors will now be shown.
In addition, you can also test for how many rows that were returned using mysql_num_rows(). For example:
if(mysql_num_rows($data) !== false)
{
while(...)
{
...
}
}
else
{
echo "No rows";
}
Will echo No rows if there weren't any results from the query. This is all error detection code; the cause of your error isn't obvious, so a little investigation is necessary, using the above methods (and any more you can think of).
Have you called mysql_select_db('your_database_name'); on the connection first? Have you tried echoing out the SQL before it's executed to confirm that Site is what you expect it to be?
$query = sprintf("SELECT * FROM Items WHERE Site ='%s'",
mysql_real_escape_string($site));
$result = mysql_query($query);
Just to be on the safe side (avoid SQL Injections).