SQL Joins

Jul 17, 2024 11:03 AM - 5 months ago 138286

SQLJoins intends combining information from 2 aliases much tables, based connected a related column. A array subordinate creates a impermanent array showing the information from the joined tables.

For example, we person 2 tables that follow, the array named tblcustomers stores the accusation astir the customer

id	Name	Address	RegDate
1	John Doe	New Delhi	2024-01-02
2	Anuj kumar	Noida UP	2024-04-01
3	Amit Singh	Bangalore Karnataka	2024-05-01
4	Alex	Chennai Tamilnadu	2024-06-09

The tbloders array shop the accusation astir the individual orders pinch their corresponding amount:

id	Customer_Id	Product_Name	Amount
1	1	iPhone	920000
2	2	Sony TV	45623
3	2	Laptop	85641
4	3	Book	456
5	4	Toys	1452

Rather than storing the customer sanction successful some tables, the tblorders array contains a reference to the customer id that appears successful tblcustomers table. We will usage subordinate to prime the corresponding information from some tables.

Syntax:

SELECT <ColumnName1>,<ColumnName2>,<ColumnNameN> From <TableName1> Join <TableName2> connected <TableName1.ColumnName1>=<TableName2.ColumnName2> Where <Condition> Order By <ColumnName1>,<ColumnName2>,<ColumnNameN>;

SELECT <ColumnName1>,<ColumnName2>,<ColumnNameN>

From <TableName1>

Join <TableName2> on <TableName1.ColumnName1>=<TableName2.ColumnName2>

Where <Condition>

Order By <ColumnName1>,<ColumnName2>,<ColumnNameN>;

In the Above Syntax:

ColumnName1 successful TableName1 is usually that table’s Primary key.
ColumnName2 successful TableName2 is simply a Foreign Key successful that table.
ColumnName1 and ColumnName2 must person the aforesaid Data Type and for definite information types, the aforesaid size.

Example utilizing the supra 2 tables tblcustomers and tblorders

SELECT tblcustomers.id, tblcustomers.Name, tblcustomers.Address, tblorders.Product_Name, tblorders.Amount FROM tblcustomers join tblorders connected tblorders.Customer_id=tblcustomers.id ORDER BY tblcustomers.id;

SELECT tblcustomers.id, tblcustomers.Name, tblcustomers.Address, tblorders.Product_Name, tblorders.Amount

FROM tblcustomers

join tblorders on tblorders.Customer_id=tblcustomers.id

ORDER BY tblcustomers.id;

Output Will be:

id	Name	Address	Product_Name	Amount
1	John Doe	New Delhi	iPhone	920000
2	Anuj kumar	Noida UP	Sony TV	45623
2	Anuj kumar	Noida UP	Laptop	85641
3	Amit Singh	Bangalore Karnataka	Book	456
4	Alex	Chennai Tamilnadu	Toys	1452