Скачать с ютуб Creating a Column that Iterates Over a Set of Numbers in Snowflake в хорошем качестве

Creating a Column that Iterates Over a Set of Numbers in Snowflake

Learn how to create a dynamic column in Snowflake that iterates over a set of numbers, similar to Oracle SQL, with an efficient solution. --- This video is based on the question https://stackoverflow.com/q/70220167/ asked by the user 'workin 4weekend' ( https://stackoverflow.com/u/11400264/ ) and on the answer https://stackoverflow.com/a/70220535/ provided by the user 'Simeon Pilgrim' ( https://stackoverflow.com/u/43992/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Set Column to iterate over set of numbers in SnowFlake Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- How to Create a Column that Iterates Over a Set of Numbers in Snowflake If you've ever worked with databases, you're likely familiar with the frustration of translating SQL commands from one system to another. Recently, one user sought help for generating a column in their Snowflake table that would iterate over a specific range of numbers—much like they did in Oracle SQL. In this post, we’ll break down the solution to this issue, providing clear guidance on how to effectively create such a column in Snowflake. The Problem The original approach in Oracle SQL looked something like this: [[See Video to Reveal this Text or Code Snippet]] This SQL code successfully updates the col_name with values cycling through 1 to 4 for each row. However, the challenge arises because the SQL function rownum does not exist in Snowflake, nor does ROW_NUMBER() work when used in an update statement. In short, the user wanted to achieve the following results: Column: col_name Values: Iterate over numbers from 1 to 4 for each subsequent row (e.g., 1, 2, 3, 4, 1, 2, 3,...). The Solution: Creating a New Table with Ordered Rows To address this problem in Snowflake, we can leverage the CREATE OR REPLACE TABLE statement combined with a SELECT query, which allows us to define how we want the table structured right from the start. Step 1: Define the New Table We will create a new table that will include the existing columns and the new iterating column. Here’s how you can construct the SQL statement: [[See Video to Reveal this Text or Code Snippet]] Step 2: Explanation of Key Components CREATING A TABLE: CREATE OR REPLACE TABLE foo AS specifies we are creating or replacing an existing table named foo. SELECTING COLUMNS: The SELECT statement pulls in the existing columns (a, b, c) while also calculating the new col_name. ROW_NUMBER() OVER: This function generates a unique number for each row based on the specified order. MODULO OPERATOR (%): The modulo operator % 4 ensures that the values cycle from 0 to 3. To adjust this to 1 to 4, you can simply add 1 to the output of the modulo. Step 3: Ordering for Performance Adding ORDER BY your, clustering, keys allows for better performance and organization of your new table, making your queries run more efficiently when you retrieve data later. Conclusion By using this method in Snowflake, you can effectively mimic the behavior of iterating over a set of numbers, similar to your previous Oracle SQL experience. This process is not only straightforward but also offers you flexibility in how you organize data in your new table. Whether you are transitioning from Oracle or just looking for ways to maximize your Snowflake efficiency, remembering to use SELECT for updates is key. Happy coding!