INNER JOIN ON vs. WHERE Clause: When Should I Use Which for Database Queries?

Inner Join on and where clause: Getting Started Guide

When connecting multiple tables in the database query, the developer can choose to use Inner Join On or where clause. Both methods are used for the same purpose: filter data according to the conditioned conditions between tables. However, there are slight differences between them.

Inner Join on Zeng Sentence

Inner Join on ON clause is a syntax recommended in ANSI SQL, especially in complex connections involving multiple tables, it is easier to read. The structure is as follows:

where clause

The method of

<code class="language-sql">SELECT ...
FROM table1 INNER JOIN table2 ON table1.foreignkey = table2.primarykey
WHERE ...</code>

where clause is more in line with the relationship data model. The format is as follows:

Equivalence in mysql

In MySQL, the use of Inner Join on and where clause is the same as Inner Join. Both inquiries will produce the same results. MySQL also offers Straight_join clauses, which can control the sequence of connection, which is a function that cannot be provided by WHERE grammar.

<code class="language-sql">SELECT ...
FROM table1, table2
WHERE table1.foreignkey = table2.primarykey AND ...</code>

Other precautions

Readability:

Inner Join on is usually considered to be easier to read, especially in complex connections.

Flexible: If necessary, Inner Join On can easily replace it with Out Join.

grammar:

Inner Join On Meets to the ANSI SQL standard, and where is rooted in the relationship data model.
• In short, Inner Join on and where clauses can be used in MySQL for Inner Join and produce the same results. However, due to the readability and ANSI compatibility of Inner Join on, it is the preferred grammar.

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