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SQLite SELECT statement

last modified July 6, 2020

This part of the SQLite tutorial covers SQLite’s implementation of the SELECT statement in detail.

SQLite retrieve all data

The following SQL statement is one of the most common ones. It is also one of the most expensive ones.

sqlite> SELECT * FROM Cars; Id Name Price

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1 Audi 52642
2 Mercedes 57127
3 Skoda 9000
4 Volvo 29000
5 Bentley 350000
6 Citroen 21000
7 Hummer 41400
8 Volkswagen 21600

Here we retrieve all data from the Cars table.

SQLite select specific columns

We can use the SELECT statement to retrieve specific columns. The column names follow the SELECT word.

sqlite> SELECT Name, Price FROM Cars; Name Price

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Audi 52642
Mercedes 57127
Skoda 9000
Volvo 29000
Bentley 350000
Citroen 21000
Hummer 41400
Volkswagen 21600

We retrieve the Name and the Price columns. The column names are separated by commas.

SQLite rename column names

We can rename the column names of the returned result set. For this, we use the AS clause.

sqlite> SELECT Name, Price AS ‘Price of car’ FROM Cars; Name Price of car

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Audi 52642
Mercedes 57127
Skoda 9000
Volvo 29000
Bentley 350000
Citroen 21000
Hummer 41400
Volkswagen 21600

With the above SQL statement, we rename the Price column to Price of car.

SQLite limit data output

As we mentioned above, retrieving all data is expensive when dealing with large amounts of data. We can use the LIMIT clause to limit the data amount returned by the statement.

sqlite> SELECT * FROM Cars LIMIT 4; Id Name Price

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1 Audi 52642
2 Mercedes 57127
3 Skoda 9000
4 Volvo 29000

The LIMIT clause limits the number of rows returned to 4.

sqlite> SELECT * FROM Cars LIMIT 2, 4; Id Name Price

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3 Skoda 9000
4 Volvo 29000
5 Bentley 350000
6 Citroen 21000

This statement selects four rows skipping the first two rows.

The OFFSET clause following LIMIT specifies how many rows to skip at the beginning of the result set. This is an alternative solution to the previous one.

sqlite> SELECT * FROM Cars LIMIT 4 OFFSET 2; Id Name Price

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3 Skoda 9000
4 Volvo 29000
5 Bentley 350000
6 Citroen 21000

Here we select all data from max four rows, and we begin with the third row. The OFFSET clause skips the first two rows.

SQLite order data

We use the ORDER BY clause to sort the returned data set. The ORDER BY clause is followed by the column on which we do the sorting. The ASC keyword sorts the data in ascending order, the DESC in descending order.

sqlite> SELECT * FROM Cars ORDER BY Price; Id Name Price

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3 Skoda 9000
6 Citroen 21000
8 Volkswagen 21600
4 Volvo 29000
7 Hummer 41400
1 Audi 52642
2 Mercedes 57127
5 Bentley 350000

The default sorting is in ascending order. The ASC clause can be omitted.

sqlite> SELECT Name, Price FROM Cars ORDER BY Price DESC; Name Price

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Bentley 350000
Mercedes 57127
Audi 52642
Hummer 41400
Volvo 29000
Volkswagen 21600
Citroen 21000
Skoda 9000

In the above SQL statement, we select Name and Price columns from the Cars table and sort it by the Price of the cars in descending order. So the most expensive cars come first.

SQLite order data by more columns

It is possible to order data by more than one column.

sqlite> INSERT INTO Cars(Name, Price) VALUES(‘Fiat’, 9000); sqlite> INSERT INTO Cars(Name, Price) VALUES(‘Tatra’, 9000);

For this example, we add two additional cars with 9000 price.

sqlite> SELECT * FROM Cars ORDER BY Price, Name DESC; Id Name Price

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10 Tatra 9000
3 Skoda 9000
9 Fiat 9000
6 Citroen 21000
8 Volkswagen 21600
4 Volvo 29000
7 Hummer 41400
1 Audi 52642
2 Mercedes 57127
5 Bentley 350000

In the statement, we sort the data by two columns: price and name. The name is in descending order.

SQLite select specific rows with WHERE

The next set of examples uses the Orders table.

sqlite> SELECT * FROM Orders; Id OrderPrice Customer

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1 1200 Williamson 2 200 Robertson 3 40 Robertson 4 1640 Smith
5 100 Robertson 6 50 Williamson 7 150 Smith
8 250 Smith
9 840 Brown
10 440 Black
11 20 Brown

Here we see all the data from the Orders table.

Next, we want to select a specific row.

sqlite> SELECT * FROM Orders WHERE Id=6; Id OrderPrice Customer

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6 50 Williamson

The above SQL statement selects a row that has Id 6.

sqlite> SELECT * FROM Orders WHERE Customer=“Smith”; Id OrderPrice Customer

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4 1640 Smith
7 150 Smith
8 250 Smith

The above SQL statement selects all orders from the Smith customer.

We can use the LIKE clause to look for a specific pattern in the data.

sqlite> SELECT * FROM Orders WHERE Customer LIKE ‘B%’; Id OrderPrice Customer

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9 840 Brown
10 440 Black
11 20 Brown

This SQL statement selects all orders from customers whose names begin with letter B.

SQLite remove duplicate items

The DISTINCT clause is used to select only unique items from the result set.

sqlite> SELECT Customer FROM Orders WHERE Customer LIKE ‘B%’; Customer

Brown
Black
Brown

This time we have selected customers whose names begin with B.
We can see that Brown appears twice. To remove duplicates, we use the DISTINCT keyword.

sqlite> SELECT DISTINCT Customer FROM Orders WHERE Customer LIKE ‘B%’; Customer

Black
Brown

This is the correct solution.

SQLite group data

The GROUP BY clause is used to combine database records with identical values into a single record. It is often used with the aggregate functions.

Say we wanted to find out the sum of each customers’ orders.

sqlite> SELECT sum(OrderPrice) AS Total, Customer FROM Orders GROUP BY Customer; Total Customer

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440 Black
860 Brown
340 Robertson 2040 Smith
1250 Williamson

The sum function returns the total sum of a numeric column. The GROUP BY clause divides the total sum among the customers. So we can see that Black has ordered items for 440 or Smith for 2040.

We cannot use the WHERE clause when aggregate functions are used. We use the HAVING clause instead.

sqlite> SELECT sum(OrderPrice) AS Total, Customer FROM Orders GROUP BY Customer HAVING sum(OrderPrice)>1000; Total Customer

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2040 Smith
1250 Williamson

The above SQL statement selects customers whose total orders where greater than 1000 units.

In this part of the SQLite tutorial, we described the SQL SELECT statement in more detail.

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