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Home  >  Article  >  Database  >  The keywords of query commands in sql are

The keywords of query commands in sql are

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2024-05-01 23:48:49558browse

The command keyword for querying data in SQL is SELECT, which is used to extract specific columns or records from a database table. The SELECT statement structure includes: SELECT [DISTINCT] FROM

[WHERE ][ORDER BY ][LIMIT ]

The keywords of query commands in sql are

Keywords for query commands in SQL: SELECT

Keywords for querying data in SQL The words are SELECT. It is used to extract specific columns or records from database tables.

SELECT statement structure: 

<code class="sql">SELECT [DISTINCT] <要提取的列名>
FROM <表名>
[WHERE <过滤条件>]
[ORDER BY <排序列>]
[LIMIT <返回记录数>]</code>

SELECT statement elements:

  • DISTINCT: Used to exclude duplicate records.
  • Column name to extract: Specify the column to be obtained from the table.
  • FROM: Specify the table to query.
  • WHERE: Specify filter conditions to filter out records that meet specific conditions.
  • ORDER BY: Specify the column by which the results will be sorted.
  • LIMIT: Specify the number of records to return.

Example:

The following statement queries the names and email addresses of all customers from the Customers table: 

<code class="sql">SELECT Name, Email
FROM Customers;</code>

The following statement queries the product names and prices with a price greater than 100 from the Products table: 

<code class="sql">SELECT Name, Price
FROM Products
WHERE Price > 100;</code>

The following statement queries all orders in the past 30 days from the Orders table , and sorted by date in descending order: 

<code class="sql">SELECT *
FROM Orders
WHERE OrderDate >= DATE('now', '-30 days')
ORDER BY OrderDate DESC;</code>

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