SQL inner [right] [left] Join

Prerequisites:

Assume there are two tables

Table1:

ID data

1

2 B

3 C

Table2:

ID data

1

2 B

4 d

Question:

1. If you want to find the same data in Table1 and Table2,

The SQL statement is: Select table1.id, table1.data, table2.id, table2.data
From Table1 inner join Table2 on (table1.data = table2.data) and (table1.id = table2.id );

The query result is:

Table1_id	Tabledomaindata	Table2_id	Table2_data
1	A	1	A
2	B	2	B

 

2. If you want to query data in Table1 and also in Table2,

The SQL statement is: Select table1.id, table1.data, table2.id, table2.data
From Table1 left join Table2 on (table1.data = table2.data) and (table1.id = table2.id );

The query result is:

Table1_id	Tabledomaindata	Table2_id	Table2_data
1	A	1	A
2	B	2	B
3	C

 

3. If you want to find the data in Table2 and also in Table1,

The SQL statement is: Select table1.id, table1.data, table2.id, table2.data
From Table1 right join Table2 on (table1.data = table2.data) and (table1.id = table2.id );

The query result is:

Table1_id	Tabledomaindata	Table2_id	Table2_data
1	A	1	A
2	B	2	B
		4	D

 

The SQL inner join, left join, right join code, and query results are as follows.

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