added dql commands

Author: AnuragAnalog

README.md

@@ -8,7 +8,7 @@ To run sql files
 source <filename>.sql;
 ```
 
-## Data Definition Language (DDl)
+## Data Definition Language (DDL)
 
 #### Create Database
 ```sql
@@ -104,7 +104,7 @@ drop table department;
 ```sql
 drop database cheatsheet;
 ```
-## Data Manipulation Language (DMl)
+## Data Manipulation Language (DML)
 
 #### Insertion (Complete)
 ```sql
@@ -136,3 +136,20 @@ delete from employee where employee_id = 2;
 ```sql
 delete from employee;
 ```
+
+## Data Query Language (DQL)
+
+#### Display Table
+```sql
+select * from employee;
+```
+
+#### Select only specified columns
+```sql
+select employee_id, first_name from employee;
+```
+
+#### Select only few rows
+```sql
+select employee_id, first_name from employee where age > 25;
+```

dql-commands.sql

@@ -0,0 +1,30 @@
+
+-- creating basic stuff to work on them
+create database cheatsheet;
+use cheatsheet;
+
+create table employee
+(
+    employee_id int primary key,              -- Setting primary key(1st method)
+    first_name varchar(50),
+    last_name varchar(50),
+    dept_number int,
+    age int,
+    salary real
+);
+
+insert into employee (employee_id, first_name, last_name, dept_number, age, salary) values (1, "Anurag", "Peddi", 1, 20, 93425.63);
+insert into employee values (2, "Anuhya", "Peddi", 2, 40, 83425.63);
+insert into employee values (3, "Vageesh", "Padigela", 3, 50, 83625.63);
+insert into employee values (4, "Rishi", "Kumar", 5, 25, 83765.23);
+insert into employee values (5, "Ashish", "Gupta", 4, 36, 103425.63);
+insert into employee values (6, "Akash", "Pippera", 6, 71, 113425.63);
+
+-- display table
+select * from employee;
+
+-- select only specified columns
+select employee_id, first_name from employee;
+
+-- select only few rows
+select employee_id, first_name from employee where age > 25;