SELECT Statement
SELECT statement is used to select data from a database. The data returned is stored in a result table, called the result-set.
Let's take an example for the given STUDENTS table.
| StudentID | FirstName | LastName | City |
|---|---|---|---|
| 1 | John | Doe | Seattle |
| 2 | Jane | Smith | San Francisco |
| 3 | Tom | Johnson | Los Angeles |
SELECT FirstName,LastName
FROM STUDENTS;
| FirstName | LastName |
|---|---|
| John | Doe |
| Jane | Smith |
| Tom | Johnson |
WHERE Clause
WHERE clause is used to filter records. The WHERE clause is used to extract only those records that fulfill a specified condition.
Let's take an example for the given STUDENTS table.
| StudentID | FirstName | LastName | City |
|---|---|---|---|
| 1 | John | Doe | Seattle |
| 2 | Jane | Smith | San Francisco |
| 3 | Tom | Johnson | Los Angeles |
SELECT FirstName,LastName
FROM STUDENTS
WHERE City='Seattle';
| FirstName | LastName |
|---|---|
| John | Doe |
ORDER BY Clause
ORDER BY clause is used to arrange the records. The ORDER BY clause can be used to arrange the records on the basis of ascending, descending order.
Let's take an example for the given STUDENTS table.
| StudentID | FirstName | LastName | City |
|---|---|---|---|
| 1 | John | Doe | Seattle |
| 2 | Jane | Smith | San Francisco |
| 3 | Tom | Johnson | Los Angeles |
SELECT FirstName,LastName
FROM STUDENTS
ORDER BY FirstName;
| FirstName | LastName |
|---|---|
| Jane | Smith |
| John | Doe |
| Tom | Johnson |
LIMIT and OFFSET Clauses
LIMIT and OFFSET clauses are used to restrict the number of records returned by a query. LIMIT clause is used to limit the number of records to return, and OFFSET clause is used to skip a specified number of records before beginning to return records.
Let's take an example for the given STUDENTS table.
| StudentID | FirstName | LastName | City |
|---|---|---|---|
| 1 | John | Doe | Seattle |
| 2 | Jane | Smith | San Francisco |
| 3 | Tom | Johnson | Los Angeles |
SELECT FirstName,LastName
FROM STUDENTS
LIMIT 2 OFFSET 1;
| FirstName | LastName |
|---|---|
| Jane | Smith |
| Tom | Johnson |