-- create CREATE TABLE EMPLOYEE ( empId INTEGER, name TEXT NOT NULL, address TEXT NOT NULL, PRIMARY KEY(empId) ); CREATE TABLE DEPT ( empId INTEGER, Dept_no TEXT NOT NULL, Salary INTEGER, Dep_name TEXT NOT NULL, foreign KEY(empId) references EMPLOYEE(empId) ); -- insert INSERT INTO EMPLOYEE VALUES (1, 'Clark', 'Delhi'); INSERT INTO EMPLOYEE VALUES (2, 'Dave', 'Chnd'); INSERT INTO EMPLOYEE VALUES (3, 'Ava', 'Mumbai'); INSERT INTO EMPLOYEE VALUES (4, 'Ana', 'Chennai'); INSERT INTO DEPT VALUES (1, 'D1', 60000, 'HR'); INSERT INTO DEPT VALUES (2, 'D2', 35000, 'IT'); INSERT INTO DEPT VALUES (3, 'D3', 45000, 'SE'); -- fetch SELECT * FROM EMPLOYEE; SELECT * FROM DEPT; -- 1. find emp who has working in a dept -- Method 1 SELECT * FROM EMPLOYEE, DEPT WHERE EMPLOYEE.empId = DEPT.empId; -- Method 2 SELECT * FROM EMPLOYEE WHERE EXISTS (SELECT * FROM DEPT WHERE DEPT.empId = EMPLOYEE.empId); -- 2. Any, All SELECT EMPLOYEE.name, DEPT.Salary FROM EMPLOYEE, DEPT WHERE DEPT.Salary > 40000 && DEPT.empId = EMPLOYEE.empId;
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MySQL is a open-source, free and very popular relational database management system which is developed, distributed and supported by Oracle corporation.
CREATE TABLE table_name (
column1 datatype,
column2 datatype,
....);
CREATE TABLE EMPLOYEE (
empId INTEGER PRIMARY KEY,
name TEXT NOT NULL,
dept TEXT NOT NULL
);
ALTER TABLE Table_name ADD column_name datatype;
INSERT INTO EMPLOYEE VALUES (0001, 'Dave', 'Sales');
TRUNCATE table table_name;
DROP TABLE table_name;
RENAME TABLE table_name1 to new_table_name1;
--Line1;
/* Line1,
Line2 */
INSERT INTO table_name (column1, column2, column3, ...) VALUES (value1, value2, value3, ...);
Note: Column names are optional.
INSERT INTO EMPLOYEE VALUES (0001, 'Ava', 'Sales');
SELECT column1, column2, ...
FROM table_name
[where condition];
SELECT * FROM EMPLOYEE where dept ='sales';
UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;
UPDATE EMPLOYEE SET dept = 'Sales' WHERE empId='0001';
DELETE FROM table_name where condition;
DELETE from EMPLOYEE where empId='0001';
CREATE INDEX index_name on table_name(column_name);
CREATE UNIQUE INDEX index_name on table_name(column_name);
DROP INDEX index_name ON table_name;
Creating a View:
CREATE VIEW View_name AS
Query;
SELECT * FROM View_name;
ALTER View View_name AS
Query;
DROP VIEW View_name;
CREATE TRIGGER trigger_name trigger_time trigger_event
ON tbl_name FOR EACH ROW [trigger_order] trigger_body
/* where
trigger_time: { BEFORE | AFTER }
trigger_event: { INSERT | UPDATE | DELETE }
trigger_order: { FOLLOWS | PRECEDES } */
DROP TRIGGER [IF EXISTS] trigger_name;
CREATE PROCEDURE sp_name(p1 datatype)
BEGIN
/*Stored procedure code*/
END;
CALL sp_name;
DROP PROCEDURE sp_name;
SELECT * FROM TABLE1 INNER JOIN TABLE2 where condition;
SELECT * FROM TABLE1 LEFT JOIN TABLE2 ON condition;
SELECT * FROM TABLE1 RIGHT JOIN TABLE2 ON condition;
SELECT select_list from TABLE1 CROSS JOIN TABLE2;