The difference between join on and join in in sql

The difference between JOIN ON and JOIN IN is: 1. JOIN ON uses equality comparison conditions, while JOIN IN can use any comparison operator; 2. JOIN IN supports subqueries, but JOIN ON cannot; 3. JOIN ON is generally more efficient than JOIN IN because it uses indexes.

The difference between JOIN ON and JOIN IN in SQL

In SQL, the JOIN operator is used to combine data from Records from multiple tables are combined together. JOIN ON and JOIN IN are two different JOIN syntaxes with different behaviors:

JOIN ON

• will match the specified conditions in the two tables. Records are grouped together. The condition is specified by the ON clause.
• The ON clause uses the equality (=) operator to compare column values ​​from two tables.
• If the condition specified in the ON clause is true, the corresponding records in the two tables will be combined.
• Syntax: JOIN table2 ON table1.column = table2.column

JOIN IN

• Groups records in a table that meet specified criteria. The condition is specified by the IN clause.
• The IN clause specifies a subquery or a list of values.
• If the value in the subquery or list matches the column value in the table, the corresponding records will be grouped together.
• Syntax: JOIN table2 ON table1.column IN (subquery or value list)

Key differences

• Comparison types: JOIN ON uses equality comparison, while JOIN IN can use any comparison operator.
• Subquery support: JOIN IN can use subqueries, but JOIN ON cannot.
• Performance: Because JOIN ON uses indexes, it is usually more efficient than JOIN IN.

Example

JOIN ON：

<code class="sql">SELECT *
FROM table1
JOIN table2
ON table1.id = table2.id;</code>

JOIN IN：

<code class="sql">SELECT *
FROM table1
JOIN table2
ON table1.id IN (SELECT id FROM table3);</code>

In the first example, records with matching IDs in table1 and table2 will be grouped together. While in the second example, the records in table1 and table2 will be combined based on the ID value in table3.

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