As we speak, Databricks publicizes help for the ANSI SQL/PSM scripting language!
SQL Scripting is now obtainable in Databricks, bringing procedural logic like looping and control-flow immediately into the SQL you already know. Scripting in Databricks is predicated on open requirements and absolutely appropriate with Apache Spark™.
For SQL-first customers, this makes it simpler to work immediately on the Lakehouse whereas profiting from Databricks’ scalability and AI capabilities.
In case you already use Databricks, you’ll discover SQL scripting particularly helpful for constructing administrative logic and ELT duties. Key options embody:
- Scoped native variables
- Native exception dealing with based mostly on symbolic error situations
- IF-THEN-ELSE and CASE help
- A number of loop constructs, together with FOR loops over queries
- Loop management with ITERATE and LEAVE
- Dynamic SQL execution by EXECUTE IMMEDIATE
Sufficient with the function listing — let’s stroll by some actual examples. You possibly can use this pocket book to observe alongside.
Knowledge administration
Administrative duties and knowledge cleanup are a continuing in enterprise knowledge administration — obligatory, routine, and not possible to keep away from. You’ll want to scrub up historic data, standardize blended codecs, apply new naming conventions, rename columns, widen knowledge sorts, and add column masks. The extra you’ll be able to automate these duties, the extra dependable and manageable your programs can be over time. One frequent instance: imposing case-insensitive habits for all STRING columns in a desk.
Let’s stroll by how SQL scripting could make this type of schema administration repeatable and easy.
Schema administration: make all STRING columns in a desk case-insensitive
On this instance, we wish to apply a brand new coverage for string sorting and comparability for each relevant column within the desk known as workers. We’ll use a typical collation sort, UTF8_LCASE, to make sure that sorting and evaluating the values on this desk will all the time be case-insensitive. Making use of this normal permits customers to learn from the efficiency advantages of utilizing collations, and simplifies the code as customers now not have to use LOWER() of their queries.
We’ll use widgets to specify which desk and collation sort to change. Utilizing the knowledge schema, we are going to then discover all current columns of sort STRING in that desk and alter their collation. We’ll acquire the column names into an array. Lastly, we are going to acquire new statistics for the altered columns, multi function script.
A pure extension of the above script is to increase it to all tables in a schema, and refresh views to select up the collation change.
Knowledge cleaning: repair grammar in free-form textual content fields
Is there any concern extra frequent on this planet of information than ‘soiled knowledge’? Knowledge from completely different programs, gadgets, and people, will inevitably have variations or errors that should be corrected. If knowledge shouldn’t be cleaned up, you’ll have unsuitable outcomes and miss an necessary perception. You possibly can count on a rubbish response in case you feed rubbish into an LLM.
Let’s have a look at an instance that features the bane of each publication, together with this weblog: typos. We’ve a desk that features free-text entries in a column known as description. The problems within the textual content, which embody spelling and grammar errors, could be obvious to anybody who is aware of English. Leaving the information on this state will undoubtedly result in points later if attempting to research or examine the textual content. Let’s repair it with SQL Scripting! First, we extract tables holding this column identify from the knowledge schema. Then repair any spelling errors utilizing ai_fix_grammar(). This perform is non-deterministic. So we use MERGE to attain our purpose.
An attention-grabbing enchancment may very well be to let ai_classify() deduce whether or not a column incorporates free-form textual content from the column identify or pattern knowledge. SQL Scripting makes administrative duties and cleansing up messy knowledge environment friendly and easy.
ETL
Prospects use SQL for ETL at the moment. Why? As a result of SQL helps a strong set of information transformation capabilities, together with joins, aggregations, filtering, with intuitive syntax, making pipeline code straightforward for any Knowledge Engineer to increase, replace, and preserve. Now, with SQL Scripting, clients can simplify beforehand advanced approaches or deal with extra advanced logic with pure SQL.
Updating a number of tables
Anybody who sells bodily merchandise can have a course of for monitoring gross sales and monitoring shipments. A typical knowledge administration sample is to mannequin a number of tables to trace transactions, shipments, deliveries, and returns. Transaction monitoring is enterprise crucial, and like all crucial course of, it requires the dealing with of surprising values. With SQL Scripting, it’s straightforward to leverage a conditional CASE assertion to parse transactions into their acceptable desk, and if an error is encountered, to catch the exception.
On this instance, we take into account a uncooked transactions desk for which rows should be routed right into a identified set of goal tables based mostly on the occasion sort. If the script encounters an unknown occasion, a user-defined exception is raised. A session variable tracks how far the script acquired earlier than it completed or encountered an exception.
This instance script may very well be prolonged with an outer loop that retains polling for extra knowledge. With SQL Scripting, you could have each the ability and adaptability to handle and replace knowledge throughout your knowledge property. SQL Scripting provides you energy to deal with any knowledge administration process and effectively management the stream of information processing.
Keep tuned to the Databricks weblog and the SQL periods on the upcoming Knowledge + AI Summit, as we put together to launch help for Temp Tables, SQL Saved Procedures, and extra!
What to do subsequent
Whether or not you’re an current Databricks person doing routine upkeep or orchestrating a large-scale migration, SQL Scripting is a functionality you must exploit. SQL Scripting is described intimately in SQL Scripting | Databricks Documentation.
You possibly can attempt these examples immediately on this SQL Scripting Pocket book. For extra particulars, keep tuned for Half 2 of this sequence, which dives into SQL Scripting constructs and how one can use them.
