How do I Combine Data from Multiple Tables in Microsoft Access using Inner Joins?

Access-SQL: Enhancing Data Accessibility with Inner Joins on Multiple Tables

Enhancing data accessibility in Microsoft Access involves effectively querying multiple tables using Join methods. Inner Join is a powerful tool that allows developers to combine data from related tables based on common fields, resulting in a single comprehensive dataset.

Performing an Inner Join for Multiple Tables Query

Consider the following scenario: You have multiple tables in your database, including tblOjt, tblStudent, tblCourse, tblCompany, and tblAddressee. Each table contains specific data about students, courses, companies, and addresses.

To retrieve specific values from these tables, such as tblOjt.id, student's full name, course, company name, addressee name, and various dates and hours, you can utilize the following SQL statement:

SELECT
  t1.id AS tblOjt_ID,
  t2.lastname || ', ' || t2.firstname || ' ' || t2.middlename AS Student_Name,
  t3.coursealias AS Course,
  t4.companyname AS Company_Name,
  t5.addresseename AS Addressee_Name,
  t1.dateadded AS Date_Added,
  t1.datestarted AS Date_Started,
  t1.dateended AS Date_Ended,
  t1.ojthours AS OJT_Hours
FROM
  ((tblOjt AS t1
  INNER JOIN tblStudent AS t2 ON t1.studentid = t2.ID)
  INNER JOIN tblCourse AS t3 ON t2.course = t3.ID)
  INNER JOIN tblCompany AS t4 ON t1.companyid = t4.ID
  INNER JOIN tblAddressee AS t5 ON t1.addresseeid = t5.ID

Understanding the Access Join Syntax

In Access, the join syntax for multiple tables follows a specific structure:

SELECT
  <column_list>
FROM
  <table1_alias>
  INNER JOIN <table2_alias> ON <join_condition>
  INNER JOIN <table3_alias> ON <join_condition>
  ...
  INNER JOIN <tableN_alias> ON <join_condition>

The LEFT JOIN or RIGHT JOIN options can be used instead of INNER JOIN to specify the type of join. However, due to the hierarchical nature of INNER JOINs, additional parentheses may be required around the later joined tables.

Conclusion

By leveraging the power of Inner Join, you can effectively extract data from multiple related tables in Access. This enhanced data accessibility empowers developers to gain valuable insights and create comprehensive reports tailored to their specific needs.

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