Getting the last id from empty mysql table [duplicate] - php

How to get the next id in mysql to insert it in the table
INSERT INTO payments (date, item, method, payment_code)
VALUES (NOW(), '1 Month', 'paypal', CONCAT("sahf4d2fdd45", id))

You can use
SELECT AUTO_INCREMENT
FROM information_schema.tables
WHERE table_name = 'table_name'
AND table_schema = DATABASE( ) ;
or if you do not wish to use information_schema you can use this
SHOW TABLE STATUS LIKE 'table_name'

You can get the next auto-increment value by doing:
SHOW TABLE STATUS FROM tablename LIKE Auto_increment
/*or*/
SELECT `auto_increment` FROM INFORMATION_SCHEMA.TABLES
WHERE table_name = 'tablename'
Note that you should not use this to alter the table, use an auto_increment column to do that automatically instead.
The problem is that last_insert_id() is retrospective and can thus be guaranteed within the current connection.
This baby is prospective and is therefore not unique per connection and cannot be relied upon.
Only in a single connection database would it work, but single connection databases today have a habit of becoming multiple connection databases tomorrow.
See: SHOW TABLE STATUS

This will return auto increment value for the MySQL database and I didn't check with other databases. Please note that if you are using any other database, the query syntax may be different.
SELECT AUTO_INCREMENT
FROM information_schema.tables
WHERE table_name = 'your_table_name'
and table_schema = 'your_database_name';
SELECT AUTO_INCREMENT
FROM information_schema.tables
WHERE table_name = 'your_table_name'
and table_schema = database();

The top answer uses PHP MySQL_ for a solution, thought I would share an updated PHP MySQLi_ solution for achieving this. There is no error output in this exmaple!
$db = new mysqli('localhost', 'user', 'pass', 'database');
$sql = "SHOW TABLE STATUS LIKE 'table'";
$result=$db->query($sql);
$row = $result->fetch_assoc();
echo $row['Auto_increment'];
Kicks out the next Auto increment coming up in a table.

In PHP you can try this:
$query = mysql_query("SELECT MAX(id) FROM `your_table_name`");
$results = mysql_fetch_array($query);
$cur_auto_id = $results['MAX(id)'] + 1;
OR
$result = mysql_query("SHOW TABLE STATUS WHERE `Name` = 'your_table_name'");
$data = mysql_fetch_assoc($result);
$next_increment = $data['Auto_increment'];

Use LAST_INSERT_ID() from your SQL query.
Or
You can also use mysql_insert_id() to get it using PHP.

Solution:
CREATE TRIGGER `IdTrigger` BEFORE INSERT ON `payments`
FOR EACH ROW
BEGIN
SELECT AUTO_INCREMENT Into #xId
FROM information_schema.tables
WHERE
Table_SCHEMA ="DataBaseName" AND
table_name = "payments";
SET NEW.`payment_code` = CONCAT("sahf4d2fdd45",#xId);
END;
"DataBaseName" is the name of our Data Base

Simple query would do
SHOW TABLE STATUS LIKE 'table_name'

For MySQL 8 use SHOW CREATE TABLE to retrieve the next autoincrement insert id:
SHOW CREATE TABLE mysql.time_zone
Result:
CREATE TABLE `time_zone` (
`Time_zone_id` int unsigned NOT NULL AUTO_INCREMENT,
`Use_leap_seconds` enum('Y','N') CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT 'N',
PRIMARY KEY (`Time_zone_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1784 DEFAULT CHARSET=utf8 STATS_PERSISTENT=0 ROW_FORMAT=DYNAMIC COMMENT='Time zones'
See the AUTO_INCREMENT=1784 at the last line of returned query.
Compare with the last value inserted:
select max(Time_zone_id) from mysql.time_zone
Result:
+-------------------+
| max(Time_zone_id) |
+-------------------+
| 1783 |
+-------------------+
Tested on MySQL v8.0.20.

SELECT id FROM `table` ORDER BY id DESC LIMIT 1
Although I doubt in its productiveness but it's 100% reliable

You have to connect to MySQL and select a database before you can do this
$table_name = "myTable";
$query = mysql_query("SHOW TABLE STATUS WHERE name='$table_name'");
$row = mysql_fetch_array($query);
$next_inc_value = $row["AUTO_INCREMENT"];

I suggest to rethink what you are doing. I never experienced one single use case where that special knowledge is required. The next id is a very special implementation detail and I wouldn't count on getting it is ACID safe.
Make one simple transaction which updates your inserted row with the last id:
BEGIN;
INSERT INTO payments (date, item, method)
VALUES (NOW(), '1 Month', 'paypal');
UPDATE payments SET payment_code = CONCAT("sahf4d2fdd45", LAST_INSERT_ID())
WHERE id = LAST_INSERT_ID();
COMMIT;

You can't use the ID while inserting, neither do you need it. MySQL does not even know the ID when you are inserting that record. You could just save "sahf4d2fdd45" in the payment_code table and use id and payment_code later on.
If you really need your payment_code to have the ID in it then UPDATE the row after the insert to add the ID.

What do you need the next incremental ID for?
MySQL only allows one auto-increment field per table and it must also be the primary key to guarantee uniqueness.
Note that when you get the next insert ID it may not be available when you use it since the value you have is only within the scope of that transaction. Therefore depending on the load on your database, that value may be already used by the time the next request comes in.
I would suggest that you review your design to ensure that you do not need to know which auto-increment value to assign next

use "mysql_insert_id()". mysql_insert_id() acts on the last performed query, be sure to call mysql_insert_id() immediately after the query that generates the value.
Below are the example of use:
<?php
$link = mysql_connect('localhost', 'username', 'password');
if (!$link) {
die('Could not connect: ' . mysql_error());
}
mysql_select_db('mydb');
mysql_query("INSERT INTO mytable VALUES('','value')");
printf("Last inserted record has id %d\n", mysql_insert_id());
?>
I hope above example is useful.

If return no correct AUTO_INCREMENT, try it:
ANALYZE TABLE `my_table`;
SELECT AUTO_INCREMENT FROM information_schema.TABLES WHERE (TABLE_NAME = 'my_table');
This clear cache for table, in BD

using the answer of ravi404:
CREATE FUNCTION `getAutoincrementalNextVal`(`TableName` VARCHAR(50))
RETURNS BIGINT
LANGUAGE SQL
NOT DETERMINISTIC
CONTAINS SQL
SQL SECURITY DEFINER
COMMENT ''
BEGIN
DECLARE Value BIGINT;
SELECT
AUTO_INCREMENT INTO Value
FROM
information_schema.tables
WHERE
table_name = TableName AND
table_schema = DATABASE();
RETURN Value;
END
using in your insert query, to create a SHA1 Hash. ex.:
INSERT INTO
document (Code, Title, Body)
VALUES (
sha1( getAutoincrementalNextval ('document') ),
'Title',
'Body'
);

Improvement of #ravi404, in case your autoincrement offset IS NOT 1 :
SELECT (`auto_increment`-1) + IFNULL(##auto_increment_offset,1)
FROM INFORMATION_SCHEMA.TABLES
WHERE table_name = your_table_name
AND table_schema = DATABASE( );
(auto_increment-1) : db engine seems to alwaus consider an offset of 1. So you need to ditch this assumption, then add the optional value of ##auto_increment_offset, or default to 1 : IFNULL(##auto_increment_offset,1)

For me it works, and looks simple:
$auto_inc_db = mysql_query("SELECT * FROM my_table_name ORDER BY id ASC ");
while($auto_inc_result = mysql_fetch_array($auto_inc_db))
{
$last_id = $auto_inc_result['id'];
}
$next_id = ($last_id+1);
echo $next_id;//this is the new id, if auto increment is on

SELECT AUTO_INCREMENT AS next_id FROM information_schema.tables WHERE table_name = 'table name' AND table_schema = 'database name of table name'

mysql_insert_id();
That's it :)

Related

MySQL generate url using already assigned ID

I'm trying to generate URL in SQL database using already assigned auto_incremented ID
When a new form is submitted then SQL automatically generates and unique lens_id for me. How can I automatically add it there in this lens_url? (Picture below)
You can do this by creating a trigger on your table. Trigger is as follows,
DELIMITER $$
CREATE TRIGGER `UpdateLensURL` BEFORE INSERT ON `your_table_name`
FOR EACH ROW BEGIN
SET NEW.lens_url= CONCAT('localhost:8888/lensview/post.php?id=', (
SELECT AUTO_INCREMENT
FROM information_schema.TABLES
WHERE TABLE_SCHEMA = DATABASE()
AND TABLE_NAME = 'your_table_name'
));
END;
$$
DELIMITER ;
There are two options here:
1) Use a stored procedure (which will require code changes for anywhere that inserts rows)
2) Use a trigger and insert as normal - something like below should do the trick:
DELIMITER //
CREATE TRIGGER my_awesome_trigger
BEFORE INSERT
ON your_table_name
FOR EACH ROW
BEGIN
DECLARE next_id int default 0;
SELECT auto_increment INTO next_id
FROM information_schema.tables
WHERE table_name = 'your_table_name'
AND table_schema = DATABASE();
SET NEW.lens_url = CONCAT('localhost:8888/.../', next_id);
END; //
DELIMITER ;
Try something like this
$qry1="insert into tablename(lens_name,lens_url,lens_category,lens_author,lens_discription,lens_repert)values('A','B','C','D','E','F')";// your query to insert data to table
mysqli_query($con,$qry1); // run query
$last_insertid=mysqli_insert_id($con); // save last insetred ID
$url="localhost:8888/lenseview/post.php?id=".$last_insertid; //prepare url
$qry2="upadte tablename set lens_url=$url where lens_id=$last_insertid"; //update query
mysqli_query($con,$qry2); // run your query to update url
I think easiest option would be this
$Last_Lens_IdQ = mysqli_query($conn, "SELECT `lens_id` FROM `table` ORDER BY `lens_id` DESC LIMIT 1");
$Last_LensId = mysqli_fetch_array($Last_Lens_IdQ);
$x = $Last_Lens[0]++;
$LensUrl = "localhost:8888/lenseview/post.php?id=".$x;
Then insert the field and use $LensUrl When inserting the lens url column

How to concat in MySql Insert Before Trigger with Select Statement of Auto Increment ID

I have four columns in a table (Names: prdRevise, prdCode, prdMfgNmbr, prdID). I am inserting values in first two columns through PHP and want to generate prdID with other three. prdMfgNmbr is autoincrement which is currently inserting '0' on new.prdMfgNmbr's place. Below is the trigger I am using.
set new.prdId = concat(new.prdCode, new.prdRevise, new.prdMfgNmbr)
following Query is giving me upcoming Auto_Increment Value. . dont know how to use it in triger.
SELECT `AUTO_INCREMENT`
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = 'labautomation'
AND TABLE_NAME = 'prdmfg';
I figured out a way to do the thing at front end in PHP:
$qry5="SELECT `AUTO_INCREMENT`FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'labautomation'AND TABLE_NAME ='prdmfg'";
$qrprId=mysql_query($qry5);
$qrMfgNmbr = mysql_fetch_assoc($qrprId);
$newqrMfgNmbr=$qrMfgNmbr['AUTO_INCREMENT'];
after getting the value I used it with other values from farm to send it into DB in prdID column. But Store procedure thing will still be appreciated.

How to lock auto_increment value?

I have a query that returns the next auto-increment value (id), and I use that value when I'm inserting data in table t_name.
SELECT AUTO_INCREMENT id
FROM information_schema.TABLES
WHERE TABLE_SCHEMA = 'db_name'
AND TABLE_NAME = 't_name'
But I want that this query gives a different value each time. E.g. Me and my pal are inserting data in db at same time, so I will get one id, he will get another. When I run this query, I want it to give me a different and incremented value each time.
Is it possible? Or do I have to create tables with sequences?
You can insert and than get the last inserted id:
$connection = mysqli_connect($rv, $username, $pass, $mydatabase);
$result = $connection->query('INSERT INTO mytable (id, name) VALUES("", "myName")');
if($result)
{ $lastId = connection->insert_id;
// so something with $lastId...
}

get columns default values as they are a row of a resultset

is there a way to get default values of columns as they are a row of a resultset?
`id` mediumint(9) NOT NULL AUTO_INCREMENT,
`state` tinyint(2) NOT NULL DEFAULT '22',
`pubdate` datetime NOT NULL DEFAULT '2012-01-01 00:00:00',
for instance a table like this should return this record:
id->NULL (?)
state->22
pubdate->2012-01-01 00:00:00
in practice, when some user opens edit.php?id=44 he will get the row 44 (update mode), but if he opens edit.php?id=0 (insert mode) I want that the fields contain default values as place holders
thank you in advance
There is a DEFAULT function
SELECT DEFAULT( id ) , DEFAULT( EXAMPLE ) FROM test LIMIT 1
With above query, it seems that you need to have atleast one record in the table as it returns no records otherwise. For current timestamp, it return a timestamp formatted string of 0s.
Sure, using the information_schema database (which stores all the information about your database structure), you can do something like:
SELECT
COLUMN_NAME,
COLUMN_DEFAULT
TABLE_NAME
FROM information_schema.COLUMNS
WHERE
TABLE_NAME='your_table_name'
AND TABLE_SCHEMA='your_database_name'
If you have a limited number of columns, you can collect them into a row using a construct like:
SELECT
id.defaultval AS id_default,
state.defaultval AS state_default,
pubdate.defaultval AS pubdate_default
FROM
(SELECT TABLE_NAME, COLUMN_DEFAULT AS defaultval FROM information_schema.COLUMNS WHERE TABLE_NAME='your_table' AND TABLE_SCHEMA='your_database' AND COLUMN_NAME='id') id
JOIN (SELECT COLUMN_DEFAULT AS defaultval FROM information_schema.COLUMNS WHERE TABLE_NAME='your_table' AND TABLE_SCHEMA='your_database' AND COLUMN_NAME='state') state ON id.TABLE_NAME = state.TABLE_NAME
JOIN (SELECT COLUMN_DEFAULT AS defaultval FROM information_schema.COLUMNS WHERE TABLE_NAME='your_table' AND TABLE_SCHEMA='your_database' AND COLUMN_NAME='pubdate') pubdate ON id.TABLE_NAME = pubdate.TABLE_NAME
Use DESCRIBE http://dev.mysql.com/doc/refman/5.0/en/describe.html
DESCRIBE sometable [somefield]
Here is php example for single field:
$resource = mysql_query("DESCRIBE sometable somefield");
$schema = mysql_fetch_assoc($resource);
$default = $schema['default'];
And here is the php example for few fields:
$resource = mysql_query("DESCRIBE sometable");
while ($schema = mysql_fetch_assoc($resource)) {
$default_list[$schema['Field']] = $schema['Default'];
}
I see no use for such a behavior and find it wrong.
It is not convenient to use. Imagine I want to enter my own state value. I'd have to delete default 22 first.
Even worse with date. Instead of setting current datetime, you are going to make me edit whole date. Why?
And for the id it is just impossible.
Why can't you just check the input fields and if empty - not to insert at all, letting database set these defaults
You just overthinked it, I believe.

Add Prefix to auto-increment in mysql db

I have my database with table test1.
It has a primary id "Id" which is auto-increment.
Now the id is in the format 1,2,3.. . .Is it possible to store the primary Id as
PNR1,PNR2,PNR3 .. . . and so on(with auto-increment).
No. Either add the prefix in the query, or use a view instead.
Not really, but you can use another column (but a view)
this is already covered here:
MySQL Auto Increment Custom Values
Yes you can do it if you have INT prefix. You have id as INT in table
// START PREFIX
$query = mysql_query("SELECT id FROM `table_name` ORDER BY id DESC LIMIT 1");
// GET THE LAST ID MAKE SURE IN TABLE YOU 9991
while ($row = mysql_fetch_object($query)) {
$lastId = $row->id;
}
list($prefix,$Id) = explode('999',$lastId );
$Id = ($Id+1);
$new_id = '999'.$Id;
// END PREFIX
$insertQuery = mysql_query("INSERT INTO `table_name` SET id = '".$new_id."',...");
Hi, I made it work in this way :
Products Table (products):
id_prod(varchar(11), NOT NULL, PK), name(varchar(40))
Products Sequence Table (productidseq):
id(AI, PK, NOT NULL)
Before Insert Trigger in Products Table:
CREATE DEFINER=`root`#`localhost` TRIGGER `dbname`.`products_BEFORE_INSERT` BEFORE INSERT ON `products` FOR EACH ROW
BEGIN
insert into productidseq (id) values(NULL);
set new.id_prod = concat('PROD or any prefix here',last_insert_id());
set #productId = new.id_prod; -- To use outside of trigger this variable is useful.
END
When you run below query :
insert into products (name) values('Bat');
data inside tables will we be like this :
products:
id | name
---|-----
1 | Bat
productidseq:
id
---
1
If any better way than this or any cons with this, please comment below. Thanks.

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