 
-- 🔄 1️⃣ View Your Current SQL Mode
SELECT @@sql_mode;
-- ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION


-- Drop if already exists
DROP TABLE IF EXISTS orders;
DROP TABLE IF EXISTS products;

-- Create products table
CREATE TABLE products (
    id INT AUTO_INCREMENT PRIMARY KEY,
    product_name VARCHAR(100),
    manufactured_date DATE,
    created_on DATETIME,
    updated_on TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);

-- Create orders table
CREATE TABLE orders (
    id INT AUTO_INCREMENT PRIMARY KEY,
    order_no VARCHAR(20),
    order_date DATE,
    delivery_date DATETIME,
    created_on TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);


-- insert
-- Valid data
INSERT INTO products (product_name, manufactured_date, created_on)
VALUES 
('Laptop', '2024-12-12', '2024-12-12 10:30:00'),
('Phone',  '2025-01-05', '2025-01-05 09:00:00');

-- fetch 
SELECT * FROM products;


/*

-- Invalid zero dates (⚠️ Will throw error under strict SQL mode)
INSERT INTO products (product_name, manufactured_date, created_on)
VALUES 
('Tablet', '0000-00-00', '0000-00-00 00:00:00');


-- ERROR 1292 (22007) at line 33: Incorrect date value: '0000-00-00' for column 'manufactured_date' at row 1

*/

-- Allow Zero Dates Temporarily (for Testing Only)
SET sql_mode = REPLACE(@@sql_mode, 'NO_ZERO_DATE', '');
SET sql_mode = REPLACE(@@sql_mode, 'NO_ZERO_IN_DATE', '');
-- ✅ This will now succeed (but should never be used in production).

SELECT @@sql_mode;


INSERT INTO products (product_name, manufactured_date, created_on)
VALUES 
('Tablet', '0000-00-00', '0000-00-00 00:00:00');

-- fetch 
SELECT * FROM products;


-- 🔙 2️⃣ Reset to Default Strict Mode (Recommended for MySQL 8.x)
-- If you changed it temporarily (e.g. removed NO_ZERO_DATE or NO_ZERO_IN_DATE), restore the default strict settings:
SET sql_mode = 'STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION';

/*
✅ This brings MySQL back to its typical safe default configuration, which:
 * rejects zero dates
 * enforces strict validation
 * avoids silent truncation of bad data
*/


-- 🧠 3️⃣ Verify After Restart
SELECT @@GLOBAL.sql_mode;
SELECT @@SESSION.sql_mode;


-- 🧹 Bonus — Detect & Clean Existing Zero Dates
SELECT id, product_name, manufactured_date, created_on
FROM products
WHERE CAST(manufactured_date AS CHAR) LIKE '0000-00%'
   OR CAST(created_on AS CHAR) LIKE '0000-00%';

-- SQL Error: 0, SQLState: S1009  - Zero date value prohibited
-- Replaces invalid datetime values ('0000-00-00', '0000-00-00 00:00:00', '0000-00-00 00:00:00.000000') with NULL
UPDATE products
SET
    manufactured_date = CASE WHEN CAST(manufactured_date AS CHAR) LIKE '0000-00%' THEN NULL ELSE manufactured_date END,
    created_on = CASE WHEN CAST(created_on AS CHAR) LIKE '0000-00%' THEN NULL ELSE created_on END
WHERE
    CAST(manufactured_date AS CHAR) LIKE '0000-00%'
 OR CAST(created_on AS CHAR) LIKE '0000-00%';
 
/*
UPDATE products
SET 
    manufactured_date = CASE 
        WHEN CAST(manufactured_date AS CHAR) IN ('0000-00-00', '0000-00-00 00:00:00', '0000-00-00 00:00:00.000000') THEN NULL 
        ELSE manufactured_date 
    END,
    created_on = CASE 
        WHEN CAST(created_on AS CHAR) IN ('0000-00-00', '0000-00-00 00:00:00', '0000-00-00 00:00:00.000000') THEN NULL 
        ELSE created_on 
    END
WHERE 
    CAST(manufactured_date AS CHAR) IN ('0000-00-00', '0000-00-00 00:00:00', '0000-00-00 00:00:00.000000')
    OR CAST(created_on AS CHAR) IN ('0000-00-00', '0000-00-00 00:00:00', '0000-00-00 00:00:00.000000');
*/
 
-- fetch 
SELECT * FROM products;

created 25 days ago by Yashwanth Merugu

MySQL online editor

Write, Run & Share MySQL queries online using OneCompiler's MySQL online editor and compiler for free. It's one of the robust, feature-rich online editor and compiler for MySQL. Getting started with the OneCompiler's MySQL editor is really simple and pretty fast. The editor shows sample boilerplate code when you choose language as 'MySQL' and start writing queries to learn and test online without worrying about tedious process of installation.

About MySQL

MySQL is a open-source, free and very popular relational database management system which is developed, distributed and supported by Oracle corporation.

Key Features:

Open-source relational database management systems.
Reliable, very fast and easy to use database server.
Works on client-server model.
Highly Secure and Scalable
High Performance
High productivity as it uses stored procedures, triggers, views to write a highly productive code.
Supports large databases efficiently.
Supports many operating systems like Linux*,CentOS*, Solaris*,Ubuntu*,Windows*, MacOS*,FreeBSD* and others.

Syntax help

Commands

1. CREATE

CREATE TABLE table_name (
                column1 datatype,
                column2 datatype,
                ....);

Example

CREATE TABLE EMPLOYEE (
  empId INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  dept TEXT NOT NULL
);

2. ALTER

ALTER TABLE Table_name ADD column_name datatype;

Example

INSERT INTO EMPLOYEE VALUES (0001, 'Dave', 'Sales');

3. TRUNCATE

TRUNCATE table table_name;

4. DROP

DROP TABLE table_name;

5. RENAME

RENAME TABLE table_name1 to new_table_name1;

6. COMMENT

Single-Line Comments:

 --Line1;

Multi-Line comments:

   /* Line1,
   Line2 */

DML Commands

1. INSERT

INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...);

Note: Column names are optional.

Example

INSERT INTO EMPLOYEE VALUES (0001, 'Ava', 'Sales');

2. SELECT

SELECT column1, column2, ...
FROM table_name
[where condition];

Example

SELECT * FROM EMPLOYEE where dept ='sales';

3. UPDATE

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;

Example

UPDATE EMPLOYEE SET dept = 'Sales' WHERE empId='0001';

4. DELETE

DELETE FROM table_name where condition;

Example

DELETE from EMPLOYEE where empId='0001';

Indexes

1. CREATE INDEX

  CREATE INDEX index_name on table_name(column_name);

To Create Unique index:

  CREATE UNIQUE INDEX index_name on table_name(column_name);

2. DROP INDEX

DROP INDEX index_name ON table_name;

Views

1. Create a View

Creating a View:
CREATE VIEW View_name AS 
Query;

2. How to call view

SELECT * FROM View_name;

3. Altering a View

ALTER View View_name AS 
Query;

4. Deleting a View

DROP VIEW View_name;

Triggers

1. Create a Trigger

CREATE TRIGGER trigger_name trigger_time trigger_event
    ON tbl_name FOR EACH ROW [trigger_order] trigger_body
/* where
trigger_time: { BEFORE | AFTER }
trigger_event: { INSERT | UPDATE | DELETE }
trigger_order: { FOLLOWS | PRECEDES } */

2. Drop a Trigger

DROP TRIGGER [IF EXISTS] trigger_name;

Stored Procedures

1. Create a Stored Procedure

CREATE PROCEDURE sp_name(p1 datatype)
BEGIN
/*Stored procedure code*/
END;

2. How to call Stored procedure

CALL sp_name;

3. How to delete stored procedure

DROP PROCEDURE sp_name;

Joins

1. INNER JOIN

SELECT * FROM TABLE1 INNER JOIN TABLE2 where condition;

2. LEFT JOIN

SELECT * FROM TABLE1 LEFT JOIN TABLE2 ON condition;

3. RIGHT JOIN

SELECT * FROM TABLE1 RIGHT JOIN TABLE2 ON condition;

4. CROSS JOIN

SELECT select_list from TABLE1 CROSS JOIN TABLE2;