This snippet of code is written in **SAS SQL (PROC...

This snippet of code is written in SAS SQL (PROC SQL), a component of the SAS programming language. Here's a breakdown of what this code does:

1. Purpose: The code creates a new table dg.dup by performing a left join operation between two existing tables, dg.dup (aliased as a) and dg.required (aliased as b), based on matching values of the column ips_sale_id.

2. Detailed Explanation:

   • proc sql;: Starts the SQL procedure in SAS.
   • create table dg.dup as: Creates or replaces a table dg.dup in the dg library to store the results of the query.
   • select b.*: Selects all columns from the dg.required table (aliased as b). Only data from table b (not from table a) will be included in the result.
   • from dg.dup a left join dg.required b: Performs a left join where:
     • Table a (dg.dup) is the "left" table in the join.
     • Table b (dg.required) is the "right" table.
     • The left join ensures that all records from table a (dg.dup) will be included in the result, even if there is no match for ips_sale_id in table b. If a match exists, the b columns will populate with values; otherwise, they will contain missing (null) values.
   • on a.ips_sale_id = b.ips_sale_id;: Specifies the join condition. Rows in table a and table b are matched based on the values in their ips_sale_id column.

3. Result:

   • The resulting table dg.dup (newly created or overwritten in the dg library) will contain all columns from table b (dg.required), and rows are determined by:
     • If a match is found between ips_sale_id in both tables (dg.dup and dg.required), the corresponding data from dg.required (b.*) is included.
     • If no match is found, b.* values will be null, but the row from a (dg.dup) will still appear in the result.

Summary:

The code:

1. Performs a left join between dg.dup and dg.required on ips_sale_id.
2. Selects all columns from dg.required in the joined results.
3. Stores (or overwrites) the result in the table dg.dup in the dg library.