SQL SELECT COUNT: A Comprehensive Guide
SQL SELECT COUNT
The SQL COUNT() function is a powerful and widely used feature to retrieve the number of records in a table. It simplifies tasks where manually counting entries would be tedious. Whether you’re working with a database of customers, products, or employees, COUNT() helps fetch accurate results efficiently.
For example, consider you have a table of registered voters in a city and need to count the total voters. Instead of manual counting, you can use SQL’s COUNT() function to achieve this instantly.
Complete Advance AI topics:-Â CLICK HERE
Complete Python Course with Advance topics:-Click here
Syntax of SQL COUNT Function
SELECT COUNT(column_name) FROM table_name;
In the syntax above:
- Replace
column_namewith the name of the column you want to count. - Replace
table_namewith the name of your table.
Examples of SQL COUNT Function
Example 1: Counting Non-NULL Values in a Column
Consider a table named Vehicles with the following data:
| Vehicle_Name | Vehicle_Type | Price |
|---|---|---|
| Tesla Model 3 | Electric | 45,000 |
| Honda Civic | Sedan | NULL |
| Ford Mustang | Sports | 60,000 |
| Toyota Corolla | Sedan | 25,000 |
| Nissan Leaf | Electric | NULL |
| BMW X5 | SUV | 80,000 |
To count the total non-NULL Price values:
SELECT COUNT(Price) AS TotalPrices FROM Vehicles;
Output:
| TotalPrices |
|---|
| 4 |
Here, COUNT(Price) excludes the NULL values, so only four rows are counted.
Example 2: Counting Total Entries in a Table
Using the same Vehicles table, if you want to count all entries, regardless of whether Price is NULL or not:
SELECT COUNT(*) AS TotalVehicles FROM Vehicles;
Output:
| TotalVehicles |
|---|
| 6 |
The COUNT(*) function includes both NULL and non-NULL values.
SQL COUNT with the WHERE Clause
You can combine COUNT() with the WHERE clause to count rows meeting specific criteria.
Example 1: Counting Rows Based on Condition
From the Vehicles table, to count the number of electric vehicles:
SELECT COUNT(Vehicle_Name) AS ElectricVehicles FROM Vehicles WHERE Vehicle_Type = 'Electric';
Output:
| ElectricVehicles |
|---|
| 2 |
Example 2: Counting Based on Another Condition
Consider another table EmployeeRecords:
| Emp_ID | Emp_Name | Salary | City |
|---|---|---|---|
| 1001 | Priya | 60,000 | Mumbai |
| 1002 | Amit | 50,000 | Delhi |
| 1003 | Ravi | 70,000 | Mumbai |
| 1004 | Sneha | 40,000 | Bangalore |
| 1005 | Arjun | 60,000 | Mumbai |
To count employees based in Mumbai:
SELECT COUNT(Emp_Name) AS EmployeesInMumbai FROM EmployeeRecords WHERE City = 'Mumbai';
Output:
| EmployeesInMumbai |
|---|
| 3 |
SQL COUNT with DISTINCT
To count only unique values, use the DISTINCT keyword with COUNT().
Example: Counting Unique Cities
From the EmployeeRecords table, count the unique cities employees belong to:
SELECT COUNT(DISTINCT City) AS UniqueCities FROM EmployeeRecords;
Output:
| UniqueCities |
|---|
| 3 |
The three unique cities are Mumbai, Delhi, and Bangalore.
Download New Real Time Projects :-Click here
Conclusion
The SQL COUNT() function is a robust tool for handling data efficiently, offering the ability to count specific or all entries in a table. Its combination with clauses like WHERE and keywords like DISTINCT further enhances its capabilities.
For more professional database management tips, stay connected with UpdateGadh!
sql select count group by
sql select count(distinct)
select count(*) from table
count number of rows in sql query result
sql count with condition
count(1) in sql
sql count if
sql average group by
sql
sql join
sql select count row
sql select count example
sql select count oracle
sql select count w3schools



Post Comment