SQL DML Statements

SQL Data Manipulation Language (DML) statements are used to manage data in the tables of a database. DML statements are used for retrieving data from a database, entering new rows to a table in database, making changes to the existing row, removing certain rows from the table etc.

SELECT Statement

SELECT statement is used to retrieve rows from a table

Syntax:

SELECT * from table_name;

SELECT col_1, col_2 from table_name;

Example:

SELECT * FROM HEALTH_DEPT;

SELECT FIRST_NAME, LAST_NAME, AGE, ADDRESS FROM HEALTH_DEPT;

INSERT Statement

INSERT statement is used to insert rows in to a table.

Syntax:

INSERT INTO table_name (col_1, col_2, … col_n) VALUES (value_1, value_2, …value_n);

INSERT INTO table_name VALUES (value_1, value_2, …value_n);

Example:

INSERT INTO HEALTH_DEPT (EMPLOYEE_ID, FIRST_NAME, LAST_NAME, SALARY) VALUES (43, Roka, Simons, 4000);

Or

INSERT INTO HEALTH_DEPT VALUES (43, Roka, Simons, 4000);




UPDATE Statement

UPDATE Statement is used to update selected rows or all rows in a table

Syntax:

UPDATE table_name SET col1=value1, col2=value2, … col_n=value_n WHERE (condition);

Example:

UPDATE HEALTH_DEPT SET SALARY=10000 WHERE ADDRESS=’Mumbai’;

DELETE Statement

This statement is used to delete rows from a table.

Syntax:

DELETE FROM table_name WHERE (condition);

Example:

DELETE FROM HEALTH_DEPT WHERE (SALARY =1000);

TRUNCATE Statement

This statement is used delete all rows from a table

Syntax:

TRUNCATE TABLE table_name

Example:

TRUNCATE TABLE HEALTH_DEPT;