create table clientes( documento char(8) not null, nombre varchar(30), domicilio varchar(30), fechaingreso date, sueldo decimal(6,2) unsigned ); create table empleados( documento char(8) not null, nombre varchar(30), domicilio varchar(30), ciudad varchar(30), provincia varchar(30) ); -- 1 Alter para añadir el campo numero de hijos a clientes alter table clientes add hijos int default 0; describe clientes; -- 2 Alter para crear un indice unico para el domicilio del cliente alter table clientes add unique index i_domicilio (domicilio); describe clientes; -- 3 Alter para crear claves primarias en ambas tablas (documento) alter table clientes add primary key (documento); describe clientes; -- 4 Alter para renombrar la tabla de "empleados" como "trabajadores" alter table empleados modify trabajadores; describe tabajadores; -- 5 Alter para cambiar el indice del punto 2 a indice no único -- 6 Mostrar los índices de ambas tablas
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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;