Pivot In SQL

How can you transform rows into columns in a SQL table?

The PIVOT function in SQL is a powerful tool for transforming rows into columns. It's particularly useful for summarizing data in a way that's easier to analyze and present. It's often used to reshape data for reporting and dashboards.

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Description

Example H2

Example H3

The PIVOT function in SQL is used to rotate rows into columns. Imagine you have a table with multiple rows of data grouped by a category, and you want to see the values for each category in separate columns. PIVOT makes this transformation straightforward. It's especially helpful when you need to aggregate data based on different categories and display the results in a tabular format suitable for reporting or analysis. For example, you might have sales data for different products in various regions, and you want to see the total sales for each product in each region. PIVOT can efficiently achieve this. It's important to understand that the values you want to pivot into columns must be known beforehand, as the function requires explicit column names for the transformation. This contrasts with other functions that might dynamically generate columns based on data.

Why Pivot In SQL is important

PIVOT is crucial for transforming data into a more usable format for reporting and analysis. It allows for a more concise and insightful presentation of aggregated data, making it easier to identify trends and patterns.

Pivot In SQL Example Usage


CREATE TABLE SalesData (
    Region VARCHAR(20),
    Product VARCHAR(20),
    Sales INT
);

INSERT INTO SalesData (Region, Product, Sales)
VALUES
('North', 'A', 100),
('North', 'B', 150),
('South', 'A', 120),
('South', 'B', 180),
('East', 'A', 140),
('East', 'B', 200);

SELECT *
FROM
(
    SELECT Region, Product, Sales
    FROM SalesData
) AS SourceTable
PIVOT (
    SUM(Sales)
    FOR Product IN ([A], [B])
) AS PivotTable;

Pivot In SQL Syntax

Common Mistakes

Forgetting to specify the aggregate function (e.g., SUM, AVG).
Incorrectly specifying the columns to pivot.
Not understanding that the values to pivot into columns must be known in advance.
Using the wrong syntax for the PIVOT clause.

Frequently Asked Questions (FAQs)

When is the SQL PIVOT function the best choice over manual CASE statements?

PIVOT shines when you need to rotate many rows into a concise, report-ready table. Instead of writing multiple SUM(CASE ...) expressions, a single PIVOT clause aggregates and transforms the data in one step, producing clean, side-by-side columns for each category—perfect for dashboards, ad-hoc analyses, or exporting to BI tools.

Why must I list every output column explicitly in a PIVOT query?

The PIVOT operator converts row values into column headers, so the database engine needs to know those headers at parse time to allocate metadata and optimize the plan. Because SQL schemas are strongly typed, dynamic column creation would break consistency checks. Therefore, you must specify the exact values that become columns (e.g., [North], [South], [West]) before the query runs.

How does Galaxy’s AI copilot accelerate writing PIVOT queries?

Galaxy detects your table schema and suggests the full PIVOT skeleton—including the column list—based on the distinct values it finds. Simply describe the result you want in plain English, and the copilot autocompletes the correct syntax, names the query, and even documents each auto-generated column. This saves you from manually inspecting data or copy-pasting repetitive CASE statements, letting you focus on analysis instead of boilerplate SQL.