# SQL

* A computer language designed for managing data in a relational database system

### Areas of Data Handling

* **Definition (DDL)**
* **Manipulation (DML)**
* **Control (DCL)**

### SQL Query Examples

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```sql
# Choose the data 
SELECT * FROM Orders;

SELECT OrderID, FirstName, LastName From Orders;

# WHERE for conditional statements 
SELECT OrderID, FirstName, LastName FROM Orders WHERE LastName = 'Walker';

# UNION command lets you join SELECT queries 
SELECT fname, lname FROM users WHERE id=$id UNION ALL SELECT socialsecuritynumber, 1 FROM secretstuff;
```

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