if not exists mysql code example

Example 1: mysql create table if not exists example

CREATE TABLE IF NOT EXISTS checklists (
    todo_id INT AUTO_INCREMENT,
    task_id INT,
    todo VARCHAR(255) NOT NULL,
    is_completed BOOLEAN NOT NULL DEFAULT FALSE,
    PRIMARY KEY (todo_id , task_id),
    FOREIGN KEY (task_id)
        REFERENCES tasks (task_id)
        ON UPDATE RESTRICT ON DELETE CASCADE
);Code language: SQL (Structured Query Language) (sql)

Example 2: not exists mysql

SELECT DISTINCT store_type FROM stores
WHERE NOT EXISTS (SELECT * FROM cities_stores
                    WHERE cities_stores.store_type = stores.store_type);

Example 3: insert if not exists mysql

INSERT INTO table_listnames (name, address, tele)
SELECT * FROM (SELECT 'Unknown' AS name, 'Unknown' AS address, '022' AS tele) AS tmp
WHERE NOT EXISTS (
    SELECT name FROM table_listnames WHERE name = 'Rupert'
) LIMIT 1;

Example 4: mysql insert into if not exists

INSERT INTO table_name (firstname, lastname)
SELECT 'NEW FIRSTNAME', 'NEW LASTNAME'
FROM DUAL
WHERE NOT EXISTS(
    SELECT 1
    FROM table_name
    WHERE firstname = 'NEW FIRSTNAME' AND lastname = 'NEW LASTNAME'
)
LIMIT 1;

Example 5: mysql insert if not exists

INSERT IGNORE INTO companies
    (id, full_name, address, phone_number)
VALUES
    (1, 'Apple', '1 Infinite Loop, Cupertino, California', 18002752273);

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Sql Example