DDL – Data Definition Language¶ Let us get an overview of DDL Statements which are typically used to create database objects such as tables. DDL Stands for Data Definition Language. We execute DDL statements less frequently as part of the application development process. Typically DDL Scripts are maintained separately than the code. Following are the …
Creating Tables and Indexes¶ Let us go through the details related to creating tables and indexes. We will also talk about how columns, constraints etc while going through the details related to tables and indexes. DDL – Data Definition Language Overview of Data Types Adding or Modifying Columns Different Types of Constraints Managing Constraints Indexes …
Solution – Daily Product Revenue¶ Let us review the Final Solution for our problem statement daily_product_revenue. Prepare tables Create tables Load the data into tables We need to project the fields which we are interested in. We need to have product_id as well as product_name as there can be products with same name and can …
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Sorting Data¶ Let us understand how to sort the data using SQL. We typically perform sorting as final step. Sorting can be done either by using one field or multiple fields. Sorting by multiple fields is also known as composite sorting. We can sort the data either in ascending order or descending order by using …
Performing Aggregations¶ Let us understand how to aggregate the data. We can perform global aggregations as well as aggregations by key. Global Aggregations Get total number of orders. Get revenue for a given order id. Get number of records with order_status either COMPLETED or CLOSED. Aggregations by key – using GROUP BY Get number of …
Joining Tables – Outer¶ Let us understand how to perform outer joins using SQL. There are 3 different types of outer joins. LEFT OUTER JOIN (default) – Get all the records from both the datasets which satisfies JOIN condition along with those records which are in the left side table but not in the right …
