only join in sql
They are functionally equivalent, but INNER JOIN can be
a bit clearer to read, especially if the query has
other join types (i.e. LEFT or RIGHT or CROSS)
included in it.only join in sql
They are functionally equivalent, but INNER JOIN can be
a bit clearer to read, especially if the query has
other join types (i.e. LEFT or RIGHT or CROSS)
included in it.how to join tables in sql
JOINING 2 Tables in sql
SELECT X.Column_Name , Y.Column_Name2
FROM TABLES1_NAME X
INNER JOIN TABLES2_NAME Y ON X.Primary_key = Y.Foreign_key;
--FOR EXAMPLE
--GET THE FIRST_NAME AND JOB_TITLE
--USE EMPLOYEES AND JOBS TABLE
--THE RELATIONSHIP IS JOB_ID
SELECT E.FIRST_NAME , J.JOB_TITLE
FROM EMPLOYEES E
INNER JOIN JOBS J ON J.JOB_ID = E.JOB_ID;joins in sql
INNER JOIN:
is used when retrieving data from multiple
tables and will return only matching data.
LEFT OUTER JOIN:
is used when retrieving data from
multiple tables and will return
left table and any matching right table records.
RIGHT OUTER JOIN:
is used when retrieving data from
multiple tables and will return right
table and any matching left table records
FULL OUTER JOIN:
is used when retrieving data from
multiple tables and will return both
table records, matching and non-matching.
INNER JOIN :
SELECT select_list From TableA A
Inner Join TableB B
On A.Key = B.Key
LEFT OUTER JOIN :
SELECT select_list From TableA A
Left Join TableB B
On A.Key = B.Key
(where b.key is null)//For delete matching data
RIGTH OUTER JOIN :
SELECT select_list From TableA A
Right Join TableB B
On A.Key = B.Key
FULL JOIN :
SELECT select_list From TableA A
FULL OUTER Join TableB B
On A.Key = B.KeyMySQL Join
A relational database consists of multiple related tables linking together using common columns which are known as foreign key columns. Because of this, data in each table is incomplete from the business perspective.
MySQL supports the following types of joins:
Inner join
Left join
Right join
Cross join
The following shows the basic syntax of the inner join clause that joins two tables table_1 and table_2:
SELECT column_list
FROM table_1
INNER JOIN table_2 ON join_condition;
SELECT column_list
FROM table_1
INNER JOIN table_2 USING (column_name);
SELECT column_list
FROM table_1
LEFT JOIN table_2 USING (column_name);
Here is the syntax of the right join:
SELECT column_list
FROM table_1
RIGHT JOIN table_2 ON join_condition;
The following shows the basic syntax of the cross join clause:
SELECT select_list
FROM table_1
CROSS JOIN table_2;sql join
-- Rows with ID existing in both a, b and c
-- JOIN is equivalent to INNER JOIN
SELECT a.ID, a.NAME, b.VALUE1, c.VALUE1 FROM table1 a
JOIN table2 b ON a.ID = b.ID
JOIN table3 c ON a.ID = c.ID
WHERE a.ID >= 1000;
-- ⇓ Test it ⇓ (Fiddle source link)join three tables sql
Suppose we are having three table named as
Student_details
Attendance_details
Batch_details
And we have to apply join these three tables for fetching records
Example query:
select column_names
from Student_detail as s join Attendance_details as a on
s.s_id = a.s_id join Batch_details as b on
s.s_id = b.s_id;
Here in the above example we implemented simple join but you change it with own join requirements.Copyright © 2021 Codeinu
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