Is join on in sql an inner join?
Yes, JOIN ON is a type of inner connection in SQL. It only returns rows with matching rows in the two tables. The comparison condition determines which rows match.
Is JOIN ON an inner join in SQL?
Answer: Yes, JOIN ON is a type of inner join in SQL.
Detailed explanation:
Inner join is a join operation that only returns rows with matching rows in the two tables. When using JOIN ON, the comparison conditions in the WHERE clause determine which rows will match.
The following is the syntax for an inner join:
<code>SELECT * FROM 表1 JOIN 表2 ON 表1.列名 = 表2.列名</code>
In this syntax:
-
SELECT *Returns the values of all columns in the two tables . -
FROM table 1andFROM table 2specify the tables to be joined. -
ON Table 1. Column Name = Table 2. Column Nameis the comparison condition, which specifies the basis for joining the two tables.
When using JOIN ON, only rows from records with matching values in the two tables will be returned. This is different from outer joins, which also return unmatched records.
Example:
Suppose we have two tables:
Table 1: Customer
| Customer ID | Customer Name |
|---|---|
| 1 | John Doe |
| 2 | Jane Smith |
Table 2: Order
| Order ID | Customer ID | Order Date |
|---|---|---|
| 1 | 1 | 2023-01-01 |
| 2 | 2 | 2023-01-02 |
Using JOIN ON, we can join these two tables to return customers that exist in both the customers table and the orders table:
<code>SELECT * FROM 客户 JOIN 订单 ON 客户.客户 ID = 订单.客户 ID</code>
The result will look like this:
| Customer ID | Customer Name | Order ID | Order Date |
|---|---|---|---|
| 1 | John Doe | 1 | 2023-01-01 |
| 2 | Jane Smith | 2 | 2023-01-02 |
The above is the detailed content of Is join on in sql an inner join?. For more information, please follow other related articles on the PHP Chinese website!
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