Working with Insert Into Ignore in Postgres
02.15.2022
Intro
When inserting multiple rows, but default SQL will stop and return an error if there is an issue and no rows are inserted. If we use the INSERT IGNORE statement we can skip errors and insert all rows that are still valid. In this article, we will learn how to use INSERT IGNORE in PostgreSQL.
The Syntax
The basic syntax of INSERT IGNORE INTO is as follows:
INSERT IGNORE INTO table(column1, column2, ...)
VALUES
(value1, value2, ....),
(value1, value2, ....);However, PSQL doesn't support INSERT IGNORE like MySql, so we need to use ON CONFLICT.
INSERT IGNORE INTO table(column1, column2, ...)
VALUES
(value1, value2, ....),
(value1, value2, ....)
On CONFLICT(column1, ....) DO NOTHING;Getting Setup
We will be using docker in this article, but feel free to install your database locally instead. Once you have docker installed, create a new file called docker-compose.yml and add the following.
version: '3'
services:
db:
image: 'postgres:latest'
ports:
- 5432:5432
environment:
POSTGRES_USER: username
POSTGRES_PASSWORD: password
POSTGRES_DB: default_database
volumes:
- psqldata:/var/lib/postgresql
phpmyadmin:
image: phpmyadmin/phpmyadmin
links:
- db
environment:
PMA_HOST: db
PMA_PORT: 3306
PMA_ARBITRARY: 1
restart: always
ports:
- 8081:80
volumes:
psqldata:Next, run docker-compose up.
Now, navigate to http://localhost:8081/ to access phpMyAdmin. Then log in with the username root and pass root_pass.
Click the SQL tab and you are ready to go.
Creating a DB
In this article, we will need some data to work with. If you don't understand these commands, don't worry, we will cover them in later articles.
We will be using the sample db provided here: https://dev.mysql.com/doc/sakila/en/. However, we will only enter what we need rather than import the whole db.
Next, let's create an film table. This is a slightly simplified version of the sakila database.
CREATE TABLE employees (
emp_no INT NOT NULL,
birth_date DATE NOT NULL,
first_name VARCHAR(14) NOT NULL,
last_name VARCHAR(16) NOT NULL,
gender VARCHAR(1),
hire_date DATE NOT NULL,
PRIMARY KEY (emp_no)
);CREATE TABLE salaries (
emp_no INT NOT NULL,
salary INT NOT NULL,
from_date DATE NOT NULL,
to_date DATE NOT NULL,
FOREIGN KEY (emp_no) REFERENCES employees (emp_no) ON DELETE CASCADE,
PRIMARY KEY (emp_no, from_date)
);Now, let's enter a few rows
INSERT INTO employees VALUES (10001,'1953-09-02','Georgi','Facello','M','1986-06-26'),
(10002,'1964-06-02','Bezalel','Simmel','F','1985-11-21'),
(10003,'1959-12-03','Parto','Bamford','M','1986-08-28'),
(10004,'1954-05-01','Chirstian','Koblick','M','1986-12-01'),
(10005,'1955-01-21','Kyoichi','Maliniak','M','1989-09-12'),
(10006,'1953-04-20','Anneke','Preusig','F','1989-06-02'),
(10007,'1957-05-23','Tzvetan','Zielinski','F','1989-02-10'),
(10008,'1958-02-19','Saniya','Kalloufi','M','1994-09-15'),
(10009,'1952-04-19','Sumant','Peac','F','1985-02-18'),
(10010,'1963-06-01','Duangkaew','Piveteau','F','1989-08-24'),
(10011,'1953-11-07','Mary','Sluis','F','1990-01-22'),
(10012,'1960-10-04','Patricio','Bridgland','M','1992-12-18'),
(10013,'1963-06-07','Eberhardt','Terkki','M','1985-10-20'),
(10014,'1956-02-12','Berni','Genin','M','1987-03-11'),
(10015,'1959-08-19','Guoxiang','Nooteboom','M','1987-07-02'),
(10016,'1961-05-02','Kazuhito','Cappelletti','M','1995-01-27'),
(10017,'1958-07-06','Cristinel','Bouloucos','F','1993-08-03'),
(10018,'1954-06-19','Kazuhide','Peha','F','1987-04-03'),
(10019,'1953-01-23','Lillian','Haddadi','M','1999-04-30'),
(10020,'1952-12-24','Mayuko','Warwick','M','1991-01-26');INSERT INTO salaries VALUES (10001,60117,'1986-06-26','1987-06-26'),
(10001,62102,'1987-06-26','1988-06-25'),
(10001,66074,'1988-06-25','1989-06-25'),
(10001,66596,'1989-06-25','1990-06-25'),
(10001,66961,'1990-06-25','1991-06-25'),
(10001,71046,'1991-06-25','1992-06-24'),
(10001,74333,'1992-06-24','1993-06-24'),
(10001,75286,'1993-06-24','1994-06-24'),
(10001,75994,'1994-06-24','1995-06-24'),
(10001,76884,'1995-06-24','1996-06-23'),
(10001,80013,'1996-06-23','1997-06-23'),
(10001,81025,'1997-06-23','1998-06-23'),
(10001,81097,'1998-06-23','1999-06-23');An Example
Let's do an example where we insert two rows with the same id. This will result in an error.
INSERT INTO employees (emp_no, birth_date, first_name, last_name, gender, hire_date)
VALUES
(4000, '1991-01-01', 'Anna', 'Hendrix', 'F', '2021-01-01'),
(4000, '1991-01-01', 'Diana', 'Hendrix', 'F', '2021-01-01');Duplicate entry '4000' for key 'employees.PRIMARY'
None of the rows were inserted. If we want the first row to insert even if the second errors, we can use the ON CONFLICT DO NOTHING.
INSERT INTO employees (emp_no, birth_date, first_name, last_name, gender, hire_date)
VALUES
(4000, '1991-01-01', 'Anna', 'Hendrix', 'F', '2021-01-01'),
(4000, '1991-01-01', 'Diana', 'Hendrix', 'F', '2021-01-01')
ON CONFLICT (emp_no) DO NOTHING;