How to add where condition in left join in mysql?

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by mac , in category: MySQL , 24 days ago

How to add where condition in left join in mysql?

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1 answer

by giovanny.lueilwitz , 21 days ago

@mac 

To add a WHERE condition in a LEFT JOIN in MySQL, you can either include the condition directly in the ON clause or in the WHERE clause. Here's how you can add a WHERE condition in a LEFT JOIN:


Method 1: Including the condition in the ON clause


SELECT column1, column2, ... FROM table1 LEFT JOIN table2 ON table1.column = table2.column AND table2.column = 'condition' WHERE ...


In this method, you add the condition within the ON clause using the AND operator.


Method 2: Including the condition in the WHERE clause


SELECT column1, column2, ... FROM table1 LEFT JOIN table2 ON table1.column = table2.column WHERE table2.column = 'condition' AND ...


In this method, you add the condition within the WHERE clause using the AND operator.


Both methods will achieve the same result. However, including the condition in the ON clause is generally preferable because it explicitly defines the relationship between the tables and optimizes the query execution.