💾 Archived View for gem.sdf.org › s.kaplan › cheatsheets › programming-languages › sql.md captured on 2024-03-21 at 15:47:31.

View Raw

More Information

⬅️ Previous capture (2023-09-28)

-=-=-=-=-=-=-

# SQL Cheatsheet

## Unique Features
- Declarative language for managing relational databases
- Used to create, modify, and query databases
- Supports ACID transactions for data consistency
- Standardized language with multiple dialects

## Data Types
- Integer: `INT`
- Decimal: `DECIMAL`
- Character: `CHAR`
- Varying character: `VARCHAR`
- Date: `DATE`
- Time: `TIME`
- Timestamp: `TIMESTAMP`
- Boolean: `BOOLEAN`

## Creating Tables

CREATE TABLE [table name] (

[column name] [data type] [optional parameters],

[column name] [data type] [optional parameters],

...

);

## Inserting Data

INSERT INTO [table name] ([column name], [column name], ...)

VALUES ([value], [value], ...);

## Updating Data

UPDATE [table name]

SET [column name] = [new value], [column name] = [new value], ...

WHERE [condition];

## Deleting Data

DELETE FROM [table name] WHERE [condition];

## Querying Data

SELECT [column name], [column name], ...

FROM [table name]

WHERE [condition]

ORDER BY [column name] [ASC/DESC];

## Joins

SELECT [column name], [column name], ...

FROM [table name 1]

JOIN [table name 2]

ON [table name 1].[column name] = [table name 2].[column name];

## Aggregation

SELECT COUNT([column name])

FROM [table name];

SELECT AVG([column name])

FROM [table name];

SELECT SUM([column name])

FROM [table name];

## Functions

MAX([column name])

MIN([column name])

UPPER([string])

LOWER([string])

SUBSTR([string], [start], [length])

## Resources
- [SQL Tutorial](https://www.w3schools.com/sql/)
- [PostgreSQL Documentation](https://www.postgresql.org/docs/)
- [MySQL Documentation](https://dev.mysql.com/doc/)