Filtering Records Based on Multiple Criteria and Dates

In this article, we will discuss how to include records based on when they first appear, excluding other records based on a certain date. We will also explore the SQL query that can be used to achieve this.

Problem Statement

We are given two tables: Table 1 and Table 2. The tables contain data related to employees and transactions, respectively. We need to select records from Table 2 based on several conditions:

• The record was first added to the database with a transaction of 222 or 223 and an activity code of ‘A’.
• The record does not have a status code of 7.
• Any records where the latest activity code (A, V, W, J) for the following transactions (109, 154, 982, 745) after 10/01/2009 should not be included in the results.

Solution

We will use a combination of SQL queries and subqueries to solve this problem. The main query will filter records based on the conditions specified above.

Subquery for Latest Activity Code

First, we need to find the latest activity code for each employee ID. We can do this by using a subquery that selects the maximum date and act_code from Table 2 for each id:

SELECT NVL(max(date), TO_DATE('01-JAN-1990','DD-MON-YYYY'))
       FROM table2 c 
       WHERE c.id = b.id
         AND c.act_code in ('A', 'V', 'W', 'J')
         AND c.trans IN (109, 154, 982, 745)

This subquery returns the maximum date for each id. If there are no rows with a trans value of either (109 or 154) and an act_code in (‘A’, ‘V’, ‘W’, ‘J’), it returns January 1st, 1990.

Main Query

Now, we can use this subquery to filter records based on the conditions specified above. Here’s the main query:

SELECT 
    Emp_id,
    statcode,
    date,
    act_code,
    trans
FROM table1 A JOIN table2 b ON (A.id = B.id)
WHERE b.trans IN(222,223)
AND b.act_code='A'
AND a.stat_code<>7
AND (SELECT NVL(max(date),TO_DATE('01-JAN-1990','DD-MON-YYYY'))
       FROM table2 c 
       WHERE c.id=b.id
         AND c.act_code in ('A', 'V', 'W', 'J')
         AND c.trans IN (109, 154, 982, 745)) <  TO_DATE('01-OCT-1990','DD-MON-YYYY');

This query filters records based on the conditions specified above. It selects only rows where:

• The transaction value is either 222 or 223.
• The activity code is ‘A’.
• The status code in Table 1 is not equal to 7.
• The latest activity code for the employee ID is before October 1st, 1990.

Result

The query returns only the records that meet all the conditions. These are the records where:

• The record was first added to the database with a transaction of 222 or 223 and an activity code of ‘A’.
• The record does not have a status code of 7.
• Any records where the latest activity code (A, V, W, J) for the following transactions (109, 154, 982, 745) after 10/01/2009 should not be included in the results.

For example, if we run this query on the provided data, it returns only one record:

| id | statcode | date | act_code | trans | | 1 | 1 | 3/4/12 | A | 222 |

This is because the first transaction value for employee ID 1 (222) meets all the conditions, and the latest activity code for this employee ID is before October 1st, 1990.

Conclusion

In conclusion, we have discussed how to include records based on when they first appear, excluding other records based on a certain date. We used a combination of SQL queries and subqueries to solve this problem. The main query filters records based on the conditions specified above, using a subquery to find the latest activity code for each employee ID.

We hope this article has helped you understand how to use SQL queries to filter records based on multiple criteria and dates. If you have any questions or need further clarification, please don’t hesitate to ask.

Last modified on 2023-10-18