#generic sql should be the perfect use case for an llm

[nem0c]

co workers talking about how SQL and power query are too complicated and they often just ask chatgpt to generate queries and then spend hours debugging them

[govindhtech]

Text to SQL LLM: What is Text to SQL And Text to SQL Methods

SQL LLM text

How text-to-SQL approaches help AI write good SQL

SQL is vital for organisations to acquire quick and accurate data-driven insights for decision-making. Google uses Gemini to generate text-to-SQL from natural language. This feature lets non-technical individuals immediately access data and boosts developer and analyst productivity.

How is Text to SQL?

A feature dubbed “text-to-SQL” lets systems generate SQL queries from plain language. Its main purpose is to remove SQL code by allowing common language data access. This method maximises developer and analyst efficiency while letting non-technical people directly interact with data.

Technology underpins

Recent Text-to-SQL improvements have relied on robust large language models (LLMs) like Gemini for reasoning and information synthesis. The Gemini family of models produces high-quality SQL and code for Text-to-SQL solutions. Based on the need, several model versions or custom fine-tuning may be utilised to ensure good SQL production, especially for certain dialects.

Google Cloud availability

Current Google Cloud products support text-to-SQL:

BigQuery Studio: available via Data Canvas SQL node, SQL Editor, and SQL Generation.

Cloud SQL Studio has “Help me code” for Postgres, MySQL, and SQLServer.

AlloyDB Studio and Cloud Spanner Studio have “Help me code” tools.

AlloyDB AI: This public trial tool connects to the database using natural language.

Vertex AI provides direct access to Gemini models that support product features.

Text-to-SQL Challenges

Text-to-SQL struggles with real-world databases and user queries, even though the most advanced LLMs, like Gemini 2.5, can reason and convert complex natural language queries into functional SQL (such as joins, filters, and aggregations). The model needs different methods to handle critical problems. These challenges include:

Provide Business-Specific Context:

Like human analysts, LLMs need a lot of “context” or experience to write appropriate SQL. Business case implications, semantic meaning, schema information, relevant columns, data samples—this context may be implicit or explicit. Specialist model training (fine-tuning) for every database form and alteration is rarely scalable or cost-effective. Training data rarely includes semantics and business knowledge, which is often poorly documented. An LLM won't know how a cat_id value in a table indicates a shoe without context.

User Intent Recognition

Natural language is less accurate than SQL. An LLM may offer an answer when the question is vague, causing hallucinations, but a human analyst can ask clarifying questions. The question “What are the best-selling shoes?” could mean the shoes are most popular by quantity or revenue, and it's unclear how many responses are needed. Non-technical users need accurate, correct responses, whereas technical users may benefit from an acceptable, nearly-perfect query. The system should guide the user, explain its decisions, and ask clarifying questions.

LLM Generation Limits:

Unconventional LLMs are good at writing and summarising, but they may struggle to follow instructions, especially for buried SQL features. SQL accuracy requires careful attention to specifications, which can be difficult. The many SQL dialect changes are difficult to manage. MySQL uses MONTH(timestamp_column), while BigQuery SQL uses EXTRACT(MONTH FROM timestamp_column).

Text-to-SQL Tips for Overcoming Challenges

Google Cloud is constantly upgrading its Text-to-SQL agents using various methods to improve quality and address the concerns identified. These methods include:

Contextual learning and intelligent retrieval: Provide data, business concepts, and schema. After indexing and retrieving relevant datasets, tables, and columns using vector search for semantic matching, user-provided schema annotations, SQL examples, business rule implementations, and current query samples are loaded. This data is delivered to the model as prompts using Gemini's long context windows.

Disambiguation LLMs: To determine user intent by asking the system clarifying questions. This usually involves planning LLM calls to see if a question can be addressed with the information available and, if not, to create follow-up questions to clarify purpose.

SQL-aware Foundation Models: Using powerful LLMs like the Gemini family with targeted fine-tuning to ensure great and dialect-specific SQL generation.

Verification and replenishment: LLM creation non-determinism. Non-AI methods like query parsing or dry runs of produced SQL are used to get a predicted indication if something crucial was missed. When provided examples and direction, models can typically remedy mistakes, thus this feedback is sent back for another effort.

Self-Reliability: Reducing generation round dependence and boosting reliability. After creating numerous queries for the same question (using different models or approaches), the best is chosen. Multiple models agreeing increases accuracy.

The semantic layer connects customers' daily language to complex data structures.

Query history and usage pattern analysis help understand user intent.

Entity resolution can determine user intent.

Model finetuning: Sometimes used to ensure models supply enough SQL for dialects.

Assess and quantify

Enhancing AI-driven capabilities requires robust evaluation. Although BIRD-bench and other academic benchmarks are useful, they may not adequately reflect workload and organisation. Google Cloud has developed synthetic benchmarks for a variety of SQL engines, products, dialects, and engine-specific features like DDL, DML, administrative requirements, and sophisticated queries/schemas. Evaluation uses offline and user metrics and automated and human methods like LLM-as-a-judge to deliver cost-effective performance understanding on ambiguous tasks. Continuous reviews allow teams to quickly test new models, prompting tactics, and other improvements.