Fundamentos de Bases de datos
C贸mo dise帽ar bases de datos y hacer queries efectivos
C贸mo identificar y organizar datos en bases de datos
Introducci贸n pr谩ctica a SQL y bases de datos relacionales
Trabajo Directo con MySQL: Cliente, Servidor y Manejo de Errores
Instalaci贸n de MySQL en varios sistemas operativos
Quiz: Fundamentos de Bases de datos
Introducci贸n a Bases de Datos Relacionales
Conceptos b谩sicos de bases de datos: columnas, tuplas y relaciones
Creaci贸n de Tablas en MySQL con Tipos de Datos Esenciales
Creaci贸n de tablas en MySQL con Primary Key y Timestamp
Normalizaci贸n y relaciones en bases de datos relacionales
Creaci贸n y visualizaci贸n de bases de datos con DBML y DBDiagram
Quiz: Introducci贸n a Bases de Datos Relacionales
Manipulaci贸n de Datos
C贸mo crear tablas y utilizar 'Foreign Keys' en MySQL
Crear tablas y establecer llaves for谩neas en SQL
Tipos de tablas en una base de datos relacional
C贸mo Modificar Tablas en SQL con ALTER TABLE
C贸mo Insertar Datos y Manejar Errores en MySQL
Creaci贸n Avanzada de una Tabla Products en MySQL
Uso pr谩ctico del WHERE en SQL para filtrar datos con precisi贸n
Gu铆a pr谩ctica para modificar datos usando UPDATE en SQL
C贸mo eliminar datos en SQL: m茅todos l贸gicos y f铆sicos
Uso Avanzado del Comando SELECT en SQL
Quiz: Manipulaci贸n de Datos
Agrupaci贸n de Datos
Funciones agregadoras en MySQL para an谩lisis eficiente de datos
Insertar datos desde otra tabla en MySQL con Insert Into Select
C贸mo utilizar Left Join en bases de datos relacionales
C贸mo consultar y relacionar tablas en MySQL
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Relational databases allow information to be efficiently connected, reducing redundant data through the use of normalization. In SQL, a key command for developing these connections is the Left Join. This command relates different tables from a common column, facilitating organized and fast queries between different datasets.
What does the Left Join do in SQL?
This type of join retrieves all the records from the left table (first table mentioned) and only the matching records from the right table. It even displays unmatched records, allowing you to detect missing data or discrepancies.
Basic example of syntax for using Left Join:
SELECT columnsFROM table1LEFT JOIN table2 ON table1.id = table2.idWHERE conditions;How to simplify SQL queries using aliases?
Aliases are a practical tool to simplify and improve the readability of SQL queries. Short names are assigned to tables or columns, helping in the quick visualization of the source of the information.
An example:
SELECT I.Investment, P.ProductID AS PID, P.Name, P.PriceFROM Investment AS ILEFT JOIN Products AS PON I.ProductID = P.ProductID;How to easily audit information using SQL queries?
Using operations within SQL itself, such as splits and comparisons, it is possible to easily audit data and ensure quality and integrity within the same query:
SELECT I.Investment, P.Stock, ROUND(I.Investment / P.Price) AS Calculated_Inventory, IF(ROUND(I.Investment / P.Price) = P.Stock, 'Perfect', 'Error') AS StatusFROM Investment AS ILEFT JOIN Products AS PON I.ProductID = P.ProductID;This type of query allows you to quickly obtain:
- Clear identification of matches or failures between tables.
- Immediate validation of the status of the data used.
Can multiple tables be connected with Left Join?
It is possible to make multiple joins between different tables using multiple Left Join statements. This greatly enhances the scope of queries by allowing complete combinations for advanced reporting, useful in more complex and detailed contexts.
These practices provide key flexibility for efficient and accurate information management in relational databases.
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