At the moment, Databricks publicizes assist for the ANSI SQL/PSM scripting language!
SQL Scripting is now accessible in Databricks, bringing procedural logic like looping and control-flow straight into the SQL you already know. Scripting in Databricks relies on open requirements and totally appropriate with Apache Spark™.
For SQL-first customers, this makes it simpler to work straight on the Lakehouse whereas benefiting 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 primarily based on symbolic error circumstances
- IF-THEN-ELSE and CASE assist
- A number of loop constructs, together with FOR loops over queries
- Loop management with ITERATE and LEAVE
- Dynamic SQL execution by means of EXECUTE IMMEDIATE
Sufficient with the characteristic record — let’s stroll by means of some actual examples. You’ll be able to use this pocket book to observe alongside.
Information administration
Administrative duties and knowledge cleanup are a continuing in enterprise knowledge administration — needed, routine, and unattainable to keep away from. You’ll want to scrub up historic data, standardize combined 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 techniques will probably be over time. One widespread instance: implementing case-insensitive conduct for all STRING columns in a desk.
Let’s stroll by means of how SQL scripting could make this sort of schema administration repeatable and simple.
Schema administration: make all STRING columns in a desk case-insensitive
On this instance, we need to apply a brand new coverage for string sorting and comparability for each relevant column within the desk known as staff. We’ll use a regular collation kind, UTF8_LCASE, to make sure that sorting and evaluating the values on this desk will at all times be case-insensitive. Making use of this customary permits customers to learn from the efficiency advantages of utilizing collations, and simplifies the code as customers not have to use LOWER() of their queries.
We’ll use widgets to specify which desk and collation kind to change. Utilizing the knowledge schema, we’ll then discover all current columns of kind STRING in that desk and alter their collation. We’ll accumulate the column names into an array. Lastly, we’ll accumulate 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.
Information cleaning: repair grammar in free-form textual content fields
Is there any challenge extra widespread on the planet of information than ‘soiled knowledge’? Information from totally different techniques, units, and people, will inevitably have variations or errors that should be corrected. If knowledge is just not cleaned up, you could have incorrect outcomes and miss an necessary perception. You’ll be able to anticipate a rubbish response if you happen to 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 now have 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 info 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 simple.
ETL
Prospects use SQL for ETL at this time. 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 simple for any Information Engineer to increase, replace, and preserve. Now, with SQL Scripting, prospects can simplify beforehand complicated approaches or deal with extra complicated logic with pure SQL.
Updating a number of tables
Anybody who sells bodily merchandise could 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 several crucial course of, it requires the dealing with of sudden values. With SQL Scripting, it’s simple 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 contemplate a uncooked transactions desk for which rows should be routed right into a recognized set of goal tables primarily based on the occasion kind. If the script encounters an unknown occasion, a user-defined exception is raised. A session variable tracks how far the script obtained 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 have got each the facility and suppleness to handle and replace knowledge throughout your knowledge property. SQL Scripting provides you energy to sort out any knowledge administration process and effectively management the circulate of information processing.
Keep tuned to the Databricks weblog and the SQL classes on the upcoming Information + AI Summit, as we put together to launch assist for Temp Tables, SQL Saved Procedures, and extra!
What to do subsequent
Whether or not you’re an current Databricks consumer doing routine upkeep or orchestrating a large-scale migration, SQL Scripting is a functionality it’s best to exploit. SQL Scripting is described intimately in SQL Scripting | Databricks Documentation.
You’ll be able to strive these examples straight on this SQL Scripting Pocket book. For extra particulars, keep tuned for Half 2 of this collection, which dives into SQL Scripting constructs and how one can use them.