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SELECT Statement

2019.08.18

The SELECT statement is used to select data from a database.

The data returned is stored in a result table, called the result-set.

SELECT Syntax

SELECT column1, column2, ...
FROM table_name;

Here, column1, column2, ... are the field names of the table you want to select data from. If you want to select all the fields available in the table, use the following syntax:

SELECT * FROM table_name;

The SQL SELECT DISTINCT Statement

The SELECT DISTINCT statement is used to return only distinct (different) values.

Inside a table, a column often contains many duplicate values; and sometimes you only want to list the different (distinct) values.

SELECT DISTINCT Syntax

SELECT DISTINCT column1, column2, ...
FROM table_name;

The SQL SELECT TOP Clause

The SELECT TOP clause is used to specify the number of records to return.

The SELECT TOP clause is useful on large tables with thousands of records. Returning a large number of records can impact performance.

Note: Not all database systems support the SELECT TOP clause. MySQL supports the LIMIT clause to select a limited number of records, while Oracle uses ROWNUM.

SQL Server / MS Access Syntax:

SELECT TOP number|percent column_name(s)
FROM table_name
WHERE condition;

MySQL Syntax:

SELECT column_name(s)
FROM table_name
WHERE condition
LIMIT number;

Oracle Syntax:

SELECT column_name(s)
FROM table_name
WHERE ROWNUM <= number;

SQL TOP, LIMIT and ROWNUM Examples

The following SQL statement selects the first three records from the "Customers" table:

Example

SELECT TOP 3 * FROM Customers;
Try it Yourself »

The following SQL statement shows the equivalent example using the LIMIT clause:

Example

SELECT * FROM Customers
LIMIT 3;
Try it Yourself »

The following SQL statement shows the equivalent example using ROWNUM:

Example

SELECT * FROM Customers
WHERE ROWNUM <= 3;

SQL TOP PERCENT Example

The following SQL statement selects the first 50% of the records from the "Customers" table:

Example

SELECT TOP 50 PERCENT * FROM Customers;
Try it Yourself »

ADD a WHERE CLAUSE

The following SQL statement selects the first three records from the "Customers" table, where the country is "Germany":

Example

SELECT TOP 3 * FROM Customers
WHERE Country='Germany';
Try it Yourself »

The following SQL statement shows the equivalent example using the LIMIT clause:

Example

SELECT * FROM Customers
WHERE Country='Germany'
LIMIT 3;
Try it Yourself »

The following SQL statement shows the equivalent example using ROWNUM:

Example

SELECT * FROM Customers
WHERE Country='Germany' AND ROWNUM <= 3;