SAS PROC SQL with DB2 Data Extraction

Proc SQL Code Explanation

The provided code snippet is written in SAS (Statistical Analysis System) and involves using PROC SQL to interact with a DB2 database. The objective of this code is to create a new table in SAS by extracting data from a table in the DB2 database.

Code Breakdown

1. PROC SQL Statement:

Proc sql;

• Purpose: Initiates the SQL procedure in SAS, allowing the execution of SQL queries.

2. Connect Statement:

Connect to db2(datasrc=DB2PRODA authdomain=DB2Auth);

• Purpose: Establishes a connection to the DB2 database using the specified data source (DB2PRODA) and authentication domain (DB2Auth).
• Components:
  • datasrc=DB2PRODA: Specifies the DB2 database source.
  • authdomain=DB2Auth: Specifies the authentication domain for accessing the DB2 database.

3. Create Table Statement:

Create table state_copy3 as 
select * from connection to db2

• Purpose: Creates a new table in SAS named state_copy3 and populates it with data selected from the DB2 database.
• Structure:
  • Create table state_copy3 as: Defines the new table state_copy3.
  • select * from connection to db2: Indicates that all data from the subsequent select query executed in the DB2 context will be copied.

4. Inner Select Statement:

(Select * from db2.state with ur);

• Purpose: Defines the query executed in the DB2 database to select all records from the state table.
• Components:
  • Select * from db2.state: Selects all columns and rows from the state table in the DB2 database.
  • with ur: Specifies a WITH UR (Uncommitted Read) isolation level, meaning the query can read uncommitted data for performance reasons.

5. Quit Statement:

Quit;

• Purpose: Ends the PROC SQL procedure, signifying the end of the SQL block.

Key Concepts

1. PROC SQL:
   • A procedure in SAS for running SQL queries.
2. Connection to DB2:
   • A method to link to an external DB2 database and run queries within it.
3. WITH UR:
   • Short for WITH UR (Uncommitted Read), an isolation level in DB2 that allows reading uncommitted changes, improving performance at the cost of potentially seeing intermediate results.

Additional Examples

Example with Specific Columns: If only specific columns are needed, the query can be adjusted:

Proc sql;
Connect to db2(datasrc=DB2PRODA authdomain=DB2Auth);
Create table state_copy3 as 
select * from connection to db2
(Select column1, column2 from db2.state with ur);
Quit;

Example with Filter Condition: To filter data based on a condition, the query can be enhanced:

Proc sql;
Connect to db2(datasrc=DB2PRODA authdomain=DB2Auth);
Create table state_copy3 as 
select * from connection to db2
(Select * from db2.state where condition_column = 'condition_value' with ur);
Quit;

Summary

This code snippet demonstrates how to connect to a DB2 database from SAS, execute an SQL query to select data from a DB2 table, and create a corresponding table in SAS with the retrieved data. The use of PROC SQL and WITH UR are key aspects of this operation, contributing to data extraction and performance optimization, respectively. Understanding these elements is essential for effectively utilizing SAS for database interactions. For further learning, accessing courses on the Enterprise DNA Platform is recommended.