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所在平台: Udemy |
课程主页: https://www.udemy.com/course/dont-go-any-interviews-without-knowing-this-sql-queries/
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课程名称：面试前必备的SQL查询知识 课程概述：SQL是当今大多数应用程序数据操作和检索的基础。掌握SQL使您能够有效地与数据库交互，从而在任何技术领域中成为更有价值的资产。本课程将指导您练习必备的SQL查询，它们将在未来解决实际问题中成为您的工具。通过练习这些查询，您不仅为面试做好准备，还能提升自己的问题解决能力，深化对数据存储、处理和检索方式的理解。请记住，持续性是关键。您练习得越多，就越能识别模式，越能快速编写优化的查询。不断挑战自己，尝试不同的场景，SQL将自然而然成为您的第二天性。 每次实践测试的问题总数：49 及格最低百分比：50% 完成每个测试的时间：60分钟 课程涵盖的主题： - 基本SQL查询：从表中选择数据，使用WHERE子句过滤记录，使用ORDER BY对结果排序。 - 字符串函数：研究CONCAT()、LEFT()、RIGHT()、SUBSTRING()、REPLACE()、CHARINDEX()、LEN()等函数，掌握字符串操作技巧。 - 日期和时间函数：如GETDATE()、YEAR()、MONTH()、DAY()、DATEDIFF()、DATEPART()、DATENAME()，处理和操作日期。 - 聚合函数：学习如何对多行执行计算以返回单一结果，例如SUM()、AVG()、COUNT()、MAX()、MIN()。 - JOIN操作：包括INNER JOIN、LEFT JOIN、RIGHT JOIN、FULL JOIN，基于相关列合并来自多个表的行。 - 子查询：使用子查询实现复杂的过滤和计算。 - 窗口函数与高级SQL：用于排名和行编号计算的函数（例如ROW_NUMBER()、RANK()）、使用OFFSET和FETCH进行分页技术。 - 索引与约束：创建和管理索引以优化查询，添加外键约束以确保引用完整性。 - 数据修改：使用INSERT、UPDATE、DELETE修改表中的数据，包括条件更新和删除。 - 架构更改：使用ALTER TABLE操作修改表结构。 - 空值处理：通过IS NULL、IS NOT NULL、COALESCE()、ISNULL()处理查询和更新中的空值。 - 条件逻辑：使用CASE语句在查询中实现条件逻辑，根据不同标准执行条件更新和选择。 祝好运！
SQL is the backbone of data manipulation and retrieval in most applications today. Mastering SQL empowers you to interact with databases efficiently, making you a more valuable asset in any technical field. The queries you practice today will become the tools you use to solve real-world problems tomorrow.By practicing these queries, you not only prepare yourself for interviews but also sharpen your problem-solving skills and deepen your understanding of how data is stored, processed, and retrieved.Remember, consistency is key. The more you practice, the more patterns you'll recognize, and the faster you'll be able to write optimized queries. Keep challenging yourself with different scenarios, and soon, SQL will become second nature to you.Total number of questions for each Practice test - 49Minimum Pass percentage - 50Time to finish each test - 60minTopics Covered in the Above SQL QueriesBasic SQL QueriesSelecting data from tables.Filtering records using WHERE clause.Ordering results with ORDER BY.String FunctionsCONCAT(), LEFT(), RIGHT(), SUBSTRING(), REPLACE(), CHARINDEX(), LEN().String manipulation techniques like concatenation, substring extraction, and searching within strings.Date and Time FunctionsGETDATE(), YEAR(), MONTH(), DAY(), DATEDIFF(), DATEPART(), DATENAME().Handling and manipulating dates, including calculating differences and extracting specific parts of a date.Aggregate FunctionsSUM(), AVG(), COUNT(), MAX(), MIN().Performing calculations on multiple rows to return a single result.JOIN OperationsINNER JOIN, LEFT JOIN, RIGHT JOIN, FULL JOIN.Combining rows from two or more tables based on related columns.SubqueriesUsing subqueries for complex filtering and calculations.Nested queries to achieve multi-step logic.Window Functions and Advanced SQLRanking and row number calculations (e.g., ROW_NUMBER(), RANK()).Pagination techniques using OFFSET and FETCH.Indexes and ConstraintsCreating and managing indexes to optimize queries.Adding constraints like FOREIGN KEY and ensuring referential integrity.Data ModificationINSERT, UPDATE, DELETE.Modifying data within tables, including condition-based updates and deletions.Schema ChangesALTER TABLE operations to modify table structures, such as adding or dropping columns.Renaming columns and tables, adding constraints.Null HandlingIS NULL, IS NOT NULL, COALESCE(), ISNULL().Techniques to handle NULL values in queries and updates.Conditional LogicUsing CASE statements for conditional logic within queries.Conditional updates and selects based on different criteria.All the best.
