H2 Database – Select
Select command is used to fetch record data from a table or multiple tables. If we design a select query, then it returns data in the form of result table called result sets.
Syntax
The basic syntax of SELECT statement is as follows −
SELECT [ TOP term ] [ DISTINCT | ALL ] selectExpression [,...] FROM tableExpression [,...] [ WHERE expression ] [ GROUP BY expression [,...] ] [ HAVING expression ] [ { UNION [ ALL ] | MINUS | EXCEPT | INTERSECT } select ] [ ORDER BY order [,...] ] [ [ LIMIT expression ] [ OFFSET expression ] [ SAMPLE_SIZE rowCountInt ] ] [ FOR UPDATE ]
To fetch all the available fields, use the following syntax.
SELECT * FROM table_name;
Example
Consider the CUSTOMER table having the following records −
+----+----------+-----+-----------+----------+ | ID | NAME | AGE | ADDRESS | SALARY | +----+----------+-----+-----------+----------+ | 1 | Ramesh | 32 | Ahmedabad | 2000.00 | | 2 | Khilan | 25 | Delhi | 1500.00 | | 3 | kaushik | 23 | Kota | 2000.00 | | 4 | Chaitali | 25 | Mumbai | 6500.00 | | 5 | Hardik | 27 | Bhopal | 8500.00 | | 6 | Komal | 22 | MP | 4500.00 | | 7 | Muffy | 24 | Indore | 10000.00 | +----+----------+-----+-----------+----------+
To get the customer table along with the given data, execute the following queries.
CREATE TABLE CUSTOMER (id number, name varchar(20), age number, address varchar(20), salary number); INSERT into CUSTOMER values (1, ''Ramesh'', 32, ''Ahmedabad'', 2000); INSERT into CUSTOMER values (2, ''Khilan'', 25, ''Delhi'', 1500); INSERT into CUSTOMER values (3, ''kaushik'', 23, ''Kota'', 2000); INSERT into CUSTOMER values (4, ''Chaitali'', 25, ''Mumbai'', 6500); INSERT into CUSTOMER values (5, ''Hardik'', 27, ''Bhopal'', 8500); INSERT into CUSTOMER values (6, ''Komal'', 22, ''MP'', 4500); INSERT into CUSTOMER values (7, ''Muffy'', 24, ''Indore'', 10000);
The following command is an example, which would fetch ID, Name and Salary fields of the customers available in the CUSTOMER table.
SELECT ID, NAME, SALARY FROM CUSTOMERS;
The above command produces the following result.
+----+----------+----------+ | ID | NAME | SALARY | +----+----------+----------+ | 1 | Ramesh | 2000.00 | | 2 | Khilan | 1500.00 | | 3 | kaushik | 2000.00 | | 4 | Chaitali | 6500.00 | | 5 | Hardik | 8500.00 | | 6 | Komal | 4500.00 | | 7 | Muffy | 10000.00 | +----+----------+----------+
Use the following query to fetch all the fields of CUSTOMERS table.
SQL> SELECT * FROM CUSTOMERS;
The above query produces the following result −
+----+----------+-----+-----------+----------+ | ID | NAME | AGE | ADDRESS | SALARY | +----+----------+-----+-----------+----------+ | 1 | Ramesh | 32 | Ahmedabad | 2000.00 | | 2 | Khilan | 25 | Delhi | 1500.00 | | 3 | kaushik | 23 | Kota | 2000.00 | | 4 | Chaitali | 25 | Mumbai | 6500.00 | | 5 | Hardik | 27 | Bhopal | 8500.00 | | 6 | Komal | 22 | MP | 4500.00 | | 7 | Muffy | 24 | Indore | 10000.00 | +----+----------+-----+-----------+----------+