Simplified SQL Query

Understanding the Original Code

The original SQL query retrieves various fields from the [Suspend Report] table while applying specific filtering conditions. It performs a LEFT JOIN with the Stock_Points table on the BRANCH field and applies several conditions in the WHERE clause.

Key Components

• Selected Fields: It selects multiple columns from the [Suspend Report].
• Conditional Logic: Uses IIf() to determine if the REQUESTED PART NO matches the SUPPLIED PART NO.
• JOIN Operation: Left join with Stock_Points on the BRANCH.
• Filtering Conditions: Excludes certain ORDER NUMBER prefixes and filters Region.

Refactored Code

We can simplify the column selections and reduce redundancy in filtering conditions. Here’s a transformed version that maintains functionality while improving clarity.

Minified SQL Query

SELECT sr.BRANCH, sr.[CUSTOMER REF], sr.[ORDER NUMBER], sr.[ITEM NUMBER], 
       sr.[REQUESTED PART NO], sr.[SUPPLIED PART NO], sr.[PART NAME], 
       sr.[CUSTOMER NAME], sr.[CUSTOMER INFORMATION],
       IIf(sr.[REQUESTED PART NO] = sr.[SUPPLIED PART NO], "MATCH", "MISMATCH") AS [MATCH], 
       sp.Region
FROM [Suspend Report] AS sr 
LEFT JOIN Stock_Points AS sp ON sr.BRANCH = sp.Branch
WHERE sr.[ORDER NUMBER] NOT LIKE "F*" 
  AND sr.[ORDER NUMBER] NOT LIKE "A*" 
  AND sr.[ORDER NUMBER] NOT LIKE "P*" 
  AND IIf(sr.[REQUESTED PART NO] = sr.[SUPPLIED PART NO], "MATCH", "MISMATCH") = "MISMATCH" 
  AND sp.Region = "QLD";

Changes Made

1. Table Aliasing: Used short aliases (sr for [Suspend Report] and sp for Stock_Points) to simplify references.
2. Removed Redundancy: Kept the IIf() condition in the WHERE clause but appended it once for better readability.
3. Clarity Improvement: Maintained logical clarity while enhancing brevity through the use of aliases and organized structure.

Test Cases and Results

Input Data

Assuming the following sample data in both tables:

• [Suspend Report]
  • BRANCH: "Branch1", ORDER NUMBER: "12345", REQUESTED PART NO: "ABC", SUPPLIED PART NO: "XYZ", ...
• Stock_Points
  • Branch: "Branch1", Region: "QLD"

Expected Output

• Output Fields: BRANCH, CUSTOMER REF, ORDER NUMBER, ITEM NUMBER, REQUESTED PART NO, SUPPLIED PART NO, PART NAME, CUSTOMER NAME, CUSTOMER INFORMATION, MATCH, Region
• Samples: Rows that have ORDER NUMBER not starting with "F", "A", or "P" and have mismatching part numbers.

Actual Output

After running the SQL query against a suitable database, validate that it returns the expected fields and filtered rows.

Conclusion

The rewritten SQL query achieves the same functionality with improved readability and efficiency, adhering to best practices in SQL writing. Test cases should be executed in an environment connected to the appropriate database to verify outcomes.