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What is the command to implement selection operation in sql

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Release： 2024-05-07 05:24:15
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Select data commands in SQL: The SELECT command extracts data from specific rows and columns from a table. Specific syntax: SELECT FROM

[WHERE ][ORDER BY [ASC|DESC]]

What is the command to implement selection operation in sql

Commands for selection operations in SQL: SELECT

The SELECT command is used to extract data for specific rows and columns from a database table.

Syntax: 

<code>SELECT <列名列表>
FROM <表名>
[WHERE <条件>]
[ORDER BY <列名> [ASC|DESC]]</code>
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Description:

  • Column name list: Specify the The extracted columns can use a single column name or multiple column names.
  • Table name: Specify the table from which to extract data.
  • WHERE clause: Can be used to filter results based on specific criteria.
  • ORDER BY clause: Can be used to sort the results by the specified column. ASC means ascending order, DESC means descending order.

Example:

Select all columns from the "customers" table: 

<code>SELECT *
FROM customers;</code>
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Select "order_id" from the "orders" table , "customer_id" and "total_amount" columns: 

<code>SELECT order_id, customer_id, total_amount
FROM orders;</code>
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Select all employees with "name" starting with "J" from the "employees" table: 

<code>SELECT name
FROM employees
WHERE name LIKE 'J%';</code>
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Select from the "products" table Products sorted in descending order by "price": 

<code>SELECT *
FROM products
ORDER BY price DESC;</code>
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