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Below is a **generic, two‑step** approach that works in most SQL engines (MySQL, PostgreSQL, SQL Server, etc.). It 1. **Creates** a new table that has the same columns as `users`. 2. **Adds** an extra `created_at` column that defaults to the current timestamp. 3. **Copies** the existing data from `users` into the new table (so you’ll have a snapshot of the current data). > **Tip** – If you’re using a specific database (e.g. MySQL, PostgreSQL, SQL Server, Oracle, etc.) let me know and I can give you the exact syntax for that system. --- ## 1️⃣ Create the new table with the same structure ```sql -- 1.1 Create an empty copy of the users table CREATE TABLE users_backup LIKE users; -- MySQL syntax -- OR CREATE TABLE users_backup AS SELECT * FROM users WHERE 1=0; -- ANSI‑SQL (works in PostgreSQL, SQL Server, etc.) ``` > *`LIKE users`* copies the column definitions, indexes, and constraints exactly. > *`SELECT * FROM users WHERE 1=0`* creates an empty table with the same columns (no data). --- ## 2️⃣ Add the `created_at` column with a default value ```sql -- 2.1 Add the column ALTER TABLE users_backup ADD COLUMN created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP; -- MySQL / PostgreSQL / SQL Server ``` > *`TIMESTAMP`* (or `DATETIME` in some engines) stores both date and time. > The `DEFAULT CURRENT_TIMESTAMP` clause ensures that any future inserts will automatically get the current date‑time. --- ## 3️⃣ (Optional) Copy the existing data into the new table If you want the backup table to contain a snapshot of the current data, run: ```sql INSERT INTO users_backup SELECT *, CURRENT_TIMESTAMP AS created_at FROM users; ``` > This copies every row from `users` and sets `created_at` to the time the row is inserted into `users_backup`. --- ### Full script (MySQL example) ```sql -- 1. Create an empty copy of the users table CREATE TABLE users_backup LIKE users; -- 2. Add the created_at column with default current timestamp ALTER TABLE users_backup ADD COLUMN created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP; -- 3. Copy existing data (optional) INSERT INTO users_backup SELECT *, CURRENT_TIMESTAMP AS created_at FROM users; ``` ### Full script (PostgreSQL example) ```sql -- 1. Create an empty copy of the users table CREATE TABLE users_backup AS SELECT * FROM users WHERE 1=0; -- 2. Add the created_at column with default current timestamp ALTER TABLE users_backup ADD COLUMN created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP; -- 3. Copy existing data (optional) INSERT INTO users_backup SELECT *, CURRENT_TIMESTAMP AS created_at FROM users; ``` --- #### What to do next? - **Verify** the new table: `SELECT * FROM users_backup LIMIT 5;` - **Adjust** indexes or constraints if needed (e.g., add a primary key, foreign keys, etc.). - **Schedule** a regular backup job if you want to keep `users_backup` up‑to‑date. Let me know if you need the exact syntax for a particular database or if you’d like help automating the backup process!Ceci est notre propre site Web avec le meilleur prix. Cliquez ici pour nos hébergements ou demandez-nous question personnelle. Ou lisez la suite avec En vacances avec votre bébé en Algarve, Portugal. , La marina et la station balnéaire de Vilamoura ou aller à l'aperçu de tous les articles.