如何自学SQL？ - 知乎
SQL是所有数据库查询的语言，sql由于本身结构化的特点，非常容易入手。 针对不同的数据库，如hivesql、mysql、sqlserver、oracle等，sql语法会有所不同，但是总体上大同小异，只是细微处的差 …
Should I use != or <> for not equal in T-SQL? - Stack Overflow
Yes; Microsoft themselves recommend using <> over != specifically for ANSI compliance, e.g. in Microsoft Press training kit for 70-461 exam, "Querying Microsoft SQL Server", they say "As an …
如何学习 SQL 语言？ - 知乎
SQL系列： 6000赞实战题目分享：如何学习 SQL 语言？ 刷题！ ！！ 新整理的 SQL 面试题： 面试数据分析会遇到的SQL题~不定时更新~ PYTHON系列： 做到这些就可以精通Python：编程零基础应当如 …
sql是什么，通俗的说，太专业听不懂？ - 知乎
SQL是一种用于处理数据的语言，就像我们说的汉语、英语一样，有特定的语法结构，让我们灵活地处理数据。 SQL并不难学，首先得理解 S Q L 三个字母分别代表什么。 Structured Query Language，简 …
sql - NOT IN vs NOT EXISTS - Stack Overflow
Which of these queries is the faster? NOT EXISTS: SELECT ProductID, ProductName FROM Northwind..Products p WHERE NOT EXISTS ( SELECT 1 FROM Northwind..[Order Details] od …
How do I perform an IF...THEN in an SQL SELECT?
Sep 15, 2008 · The CASE statement is the closest to IF in SQL and is supported on all versions of SQL Server.
SQL: IF clause within WHERE clause - Stack Overflow
Sep 18, 2008 · Is it possible to use an IF clause within a WHERE clause in MS SQL? Example: WHERE IF IsNumeric(@OrderNumber) = 1 OrderNumber = @OrderNumber ELSE OrderNumber LIKE '%' + @
通俗易懂的学会：SQL窗口函数 - 知乎
Oct 12, 2025 · 视频《最通俗易懂的学会SQL窗口函数》 SQL从入门到进阶 (视频+社群) 3.聚合函数作为窗口函数 聚和窗口函数和上面提到的专用窗口函数用法完全相同，只需要把聚合函数写在窗口函数 …
sql - Delete duplicate rows keeping the first row - Stack Overflow
10 To delete the duplicate rows from the table in SQL Server, you follow these steps: Find duplicate rows using GROUP BY clause or ROW_NUMBER () function. Use DELETE statement to remove the …
sql - Insert into ... values ( SELECT ... FROM ... ) - Stack Overflow
Aug 25, 2008 · Is there a silver-bullet syntax coming from an SQL standard (for example, SQL-92) that would allow me to insert the values without worrying about the underlying database?