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SQL Database CommandsCheat Sheet

Master database operations with comprehensive SQL commands and examples

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50+ Commands
All Skill Levels
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1
CRUD Operations

SELECT Statement

Retrieve data from one or more tables

SELECT column1, column2 FROM table_name WHERE condition;
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Example:
SELECT name, age FROM users WHERE age > 18;
Quick Tip:
Always specify columns instead of using * for better performance

INSERT Statement

Add new records to a table

INSERT INTO table_name (column1, column2) VALUES (value1, value2);
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Example:
INSERT INTO users (name, email) VALUES ('John Doe', 'john@example.com');
Quick Tip:
Use parameterized queries to prevent SQL injection

UPDATE Statement

Modify existing records in a table

UPDATE table_name SET column1 = value1 WHERE condition;
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Example:
UPDATE users SET age = 25 WHERE name = 'John Doe';
Quick Tip:
Always use WHERE clause to avoid updating all rows

DELETE Statement

Remove records from a table

DELETE FROM table_name WHERE condition;
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Example:
DELETE FROM users WHERE age < 18;
Quick Tip:
Be very careful with DELETE - always test with SELECT first

TRUNCATE TABLE

Remove all records from a table quickly

TRUNCATE TABLE table_name;
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Example:
TRUNCATE TABLE temp_data;
Quick Tip:
Faster than DELETE but cannot be rolled back in some databases

CREATE TABLE

Create a new table with specified columns and data types

CREATE TABLE table_name (column1 datatype, column2 datatype, ...);
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Example:
CREATE TABLE users (id INT PRIMARY KEY, name VARCHAR(100), email VARCHAR(255));
Quick Tip:
Always define primary keys and appropriate data types

ALTER TABLE

Modify existing table structure

ALTER TABLE table_name ADD/DROP/MODIFY column_name datatype;
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Example:
ALTER TABLE users ADD phone VARCHAR(20);
Quick Tip:
Be careful with DROP COLUMN - data will be lost permanently