SQL TABLE

What does TABLE mean in SQL?

Defines or references a named, structured collection of columns and rows stored in a database.

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Compatible dialects for SQL TABLE:

SQL TABLE Full Explanation

TABLE is the core relational object that stores data in a database. It appears in Data Definition Language (DDL) commands such as CREATE TABLE, ALTER TABLE, and DROP TABLE, and in Data Manipulation Language (DML) queries like SELECT, INSERT, UPDATE, and DELETE. A table consists of one or more columns, each with a data type, optional constraints, and optional default values. Rows represent individual records. When you define a table you also implicitly define its metadata, including column order, constraints, indexes, and storage parameters. Proper table design underpins performance, integrity, and scalability. Caveats: column order cannot be changed easily in many systems, most databases lock or block writes during structural changes, and dropping a table is irreversible unless wrapped in a transaction or backup.

SQL TABLE Syntax

-- Creating a table
CREATE TABLE table_name (
    column_name1 data_type [constraint],
    column_name2 data_type [constraint],
    ...
);

-- Referencing an existing table
SELECT * FROM table_name;

-- Modifying a table
ALTER TABLE table_name ADD column_name3 data_type;

-- Removing a table
DROP TABLE table_name;

SQL TABLE Parameters

Example Queries Using SQL TABLE

-- Basic table creation
CREATE TABLE employees (
    id            SERIAL PRIMARY KEY,
    first_name    VARCHAR(50) NOT NULL,
    last_name     VARCHAR(50) NOT NULL,
    hired_at      DATE DEFAULT CURRENT_DATE,
    salary        NUMERIC(12,2) CHECK (salary > 0)
);

-- Insert and query
INSERT INTO employees (first_name, last_name, salary)
VALUES ('Ada', 'Lovelace', 120000.00);

SELECT id, first_name, salary FROM employees;

-- Alter structure
ALTER TABLE employees ADD COLUMN department_id INT;

-- Remove table when no longer needed
DROP TABLE employees;

Expected Output Using SQL TABLE

CREATE TABLE allocates an empty, structured data container
INSERT adds a row
SELECT returns the inserted data
ALTER TABLE adds a new column
DROP TABLE deletes the table definition and all its data

Use Cases with SQL TABLE

Designing a new schema for an application
Staging raw data before transformation
Partitioning data across multiple tables for performance
Creating temporary tables for intermediate analytics
Archiving historical records into dedicated tables

Common Mistakes with SQL TABLE

Forgetting PRIMARY KEY or UNIQUE constraints, leading to duplicate data
Using overly generic data types like TEXT for every column
Dropping a table in production without a backup
Assuming column order is meaningful after frequent schema changes
Mixing transactional and analytical workloads in the same table, causing lock contention

First Introduced In

SQL-86 (ANSI X3.135-1986)

Frequently Asked Questions

What is the minimum required to create a table?

A table only needs a name and at least one column with a data type, but best practice is to include a primary key.

How do I rename a table?

Use ALTER TABLE old_name RENAME TO new_name; in dialects like PostgreSQL and SQLite. In MySQL use RENAME TABLE.

When should I use temporary tables?

Use TEMP or TEMPORARY tables for intermediate results in complex reporting or ETL jobs to avoid polluting the main schema.

What happens to indexes when I drop a table?

All indexes, constraints, and triggers tied to the table are automatically removed along with the table definition and data.