This question already has answers here:
What's the PostgreSQL datatype equivalent to MySQL AUTO INCREMENT?
(11 answers)
Auto increment table column
(4 answers)
Closed 9 years ago.
In mySQL i am able to do
INSERT INTO table_name (column_name1, column_name2) VALUES('John', 'Doe);
As you can see I do not have to mention the ID, how would I do this in postgreSQL.
Thank you
Approach #1:
You can declare your ID column as Serial
In this case it will create an implicit sequence for your column.
Example :
CREATE TABLE MyTable
(
ID serial NOT NULL,
column1 type,
column2 type
}
Approach #2:
Or you can manually define a sequence and then assign its next value as Default value for the column.
CREATE SEQUENCE my_sequence START 1;
CREATE TABLE MyTable
(
ID integer DEFAULT nextval('my_sequence'::regclass) NOT NULL,
column1 type,
column2 type
}
This is not because of mysql that happens. You can make such this kind of query because you have set id as an auto_increment column
You can actually do the same thing in postgreSQL by using the serial pseudo data type instead
Example of primary column serial
id serial PRIMARY KEY,
Related
Based on my question above, I have a MySQL table called qrc_creation. This table consists of columns like id (auto increment), creation_code, and creation_name. For example, if I want to insert a new creation_name, the ID will auto 1. But, I also want the creation_code to become qrc_00000001, where 1 comes from ID.
Thus, can I know what is the query to do this? Thank you in advance!
You have two options. If you want, the column to autopopulate during insert, you can use MySQL generated columns while defining table schema. However, you cannot use Auto Increment column with this method.
CREATE TABLE `table_1` (
`id` INT(10) ZEROFILL NOT NULL,
`creation_name` VARCHAR(45) NOT NULL,
`creation_code` VARCHAR(55) GENERATED ALWAYS AS (CONCAT(`name`, '_', `id`)),
PRIMARY KEY (`id`));
If you don't want that dedicated column in your table, you can easily get calculated field on your SQL query by using a simple concat function.
SELECT
`id`, `creation_name`, CONCAT(`name`, '_', `id`) AS `creation_code`
FROM
table_1;
Hope it helps.
first of all you need to show your code so that stackoverflow community respond. But still i got your problem and given below is the solution-
CREATE TABLE qrc_creation
(ID INT IDENTITY(1,1) NOT NULL PRIMARY KEY CLUSTERED,
creation_code AS 'qrc' + RIGHT('0000000' + CAST(ID AS VARCHAR(7)), 7) PERSISTED,
creation_name varchar(255),
);
Select * from qrc_creation;
INSERT INTO qrc_creation(creation_name)
VALUES ('Monsen');
Select * from qrc_creation;
Hope you like my answer.
This question already has answers here:
How to set initial value and auto increment in MySQL?
(10 answers)
Closed 1 year ago.
Am trying to create a MySQL that tells
auto_increment
Where and how to start incrementing. Each time I run the code, it always tells me I have error near
auto.
Each time I removed the "=", it always work.
This is the code
CREATE TABLE staff(
id into(11) not null primary key auto_increment=001,
Names varchar(109) not null
);
What am I doing wrong
First create table like below:
CREATE TABLE staff( id into(11) not null primary key
auto_increment, Names varchar(109) not null );
then alter to customized auto increment.
ALTER TABLE staff AUTO_INCREMENT=001;
Schema (MySQL v5.7)
CREATE TABLE staff(
id int not null primary key auto_increment,
Names varchar(255) not null
)auto_increment=001;
View on DB Fiddle
The default auto-increment value is an option on the table not on the column (perhaps counterintuitively, but a table is only allowed to have one such column).
The syntax looks like:
CREATE TABLE staff (
id int not null primary key auto_increment,
Names varchar(109) not null
) auto_increment = 10;
Here is a db<>fiddle.
This question already has an answer here:
#1136 - Column count doesn't match value count?
(1 answer)
Closed 3 years ago.
Created a table using the following SQL statement in phpmyadmin.
CREATE TABLE User (
user_id INTEGER NOT NULL AUTO_INCREMENT KEY,
name VARCHAR(128) UNIQUE
) ENGINE=InnoDB CHARACTER SET=utf8;
When I try to do a insert using the following insert statement I get the error "#1136 - Column count doesn't match value count at row 1"
INSERT INTO User (user_id, name) VALUES ('Taliesin');
I made the user_id a primary key in phpmyadmin but I still get this error. Shouldn't the user_id be auto inserted when the column is set to AUTO INCREMENT? Thank you.
you don't need to specify two columns since one is auto incremented
INSERT INTO User(name) VALUES('Taliesin')
i understand,below column will be signed int by default.
id INT(6);
Can an auto increment column specified below be signed by default? Mysql starts the value from 1 for an auto increment column.
id INT(6) AUTO_INCREMENT PRIMARY KEY
Yes, you can create an auto increment primary key with a signed int. Try this:
CREATE TABLE mytable( id int(6) AUTO_INCREMENT PRIMARY KEY);
Then the following queries are both valid
INSERT INTO mytable values();
INSERT INTO mytable values(-10);
This will result in the table having a row with -10 and another with 1 as values. But you will run into problems if you try this:
ALTER TABLE mytable AUTO_INCREMENT=-10;
yes, you cannot have auto increment values that are negative numbers.
After a lot of searches... I looked for a solution with a TRIGGER called BEFORE INSERT ! I found this : https://stackoverflow.com/a/43441586/2282880
Here is my variant :
CREATE TRIGGER `invertID`
BEFORE INSERT ON `<table>`
FOR EACH ROW SET NEW.id=CONCAT("-", (
SELECT `auto_increment`
FROM INFORMATION_SCHEMA.TABLES
WHERE table_name = '<table>')
)
It worked for me fine.
It was the best way I found to sync in both directions two databases with same schema without same ID's in my tables.
I want to know the next value of auto increment field
I wanted to test this :
select max(contactid) from contact
and I add 1
but I realized that it can give me an error
for exemple
if I insert one record and I delete it
so if I insert after the field will increase by two
how can I achieve that ?
thank you
There are multiple solutions to this problem:
1. (Preferable) Stop trying to predict auto-increment values
This is the more typical case, and basically is using auto-increment as designed. This assumes that you don't actually need the auto-increment value before you insert. What you can do is:
DROP TABLE IF EXISTS t;
CREATE TABLE t (id INT UNSIGNED NOT NULL auto_increment, x INT NOT NULL, PRIMARY KEY(id));
INSERT INTO t (x) VALUES (100);
SELECT LAST_INSERT_ID();
The call to SELECT LAST_INSERT_ID() will return the ID that was just generated for your INSERT.
2. Set up an ID generation table specifically to generate IDs
You can create a table with just an auto-increment column, like so:
DROP TABLE IF EXISTS id_generator;
CREATE TABLE id_generator (id INT UNSIGNED NOT NULL auto_increment, PRIMARY KEY(id));
You can then generate a new, unique ID with:
INSERT INTO id_generator (id) VALUES (NULL);
SELECT LAST_INSERT_ID();
And use that ID to insert into the table you're actually working with. As long as all generated IDs come from this ID generation table, there will be no conflicts. However there is a cost to generating these IDs, and auto-increment is not very efficient at it.
3. Use an external ID generation scheme
This is more or less similar to solution 2, but doesn't use MySQL at all for the ID generation. You can use something like a UUID/GUID scheme which generates a string, or you could use something like Snowflake to generate integer IDs.
You should use LAST_INSERT_ID like this:
SELECT LAST_INSERT_ID()
It will return the last value of AUTO_INCREMENT ID field.
More details here: http://goo.gl/RkmR5
This will give you the next id value that will be inserted:
SELECT LAST_INSERT_ID() + 1;