Database Fundamentals/Selecting Data

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This lesson introduces selecting data.

Objectives and Skills[edit | edit source]

Objectives and skills for the selecting data portion of Microsoft Exam 98-364 Database Fundamentals include:[1]

  • Manipulate data
    • Select data
      • Utilize SELECT queries to extract data from one table, extract data by using joins, combine result sets by using UNION and INTERSECT

Readings[edit | edit source]

  1. Wikipedia: Select (SQL)

Multimedia[edit | edit source]

  1. Microsoft Virtual Academy: Using DML Statements
  2. YouTube: Introducing Query Design
  3. YouTube: SQL Server Queries Part 1 - Writing Basic Queries
  4. YouTube: SQL JOIN Statement

Activities[edit | edit source]

  1. Use SQL Server to list items from the Student and Course tables in your College database.
  2. Write the following queries:

Lesson Summary[edit | edit source]

  • A SELECT statement retrieves zero or more rows from one or more database tables or database views.[2]
  • A SQL join clause combines records from two or more tables in a relational database. A JOIN is a means for combining fields from two tables (or more) by using values common to each. .[3]
  • A CROSS JOIN will produce rows which combine each row from the first table with each row from the second table.[4]
  • A INTERSECT clause combines the results of two queries and returns only rows that appear in both result sets. For purposes of duplicate removal the INTERSECT operator does not distinguish between NULLs. The INTERSECT operator removes duplicate rows from the final result set.[5]
  • A UNION clause combines the results of two SQL queries into a single table of all matching rows. The two queries must result in the same number of columns and compatible data types in order to unite.[6]

Key Terms[edit | edit source]

cross join

See Also[edit | edit source]

References[edit | edit source]

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