Excel
Avoiding Misleading Axes in Excel Charts Built From Data
Avoid misleading axes in Excel charts: start bars at zero, set scales on purpose, avoid dual axes, use consistent scales across charts and label the units.
7 min read
Topic
Data Analysis
Answers from raw rows: aggregates, cohorts, funnels, time series, plus the string and text wrangling that precedes every report.
Excel
Exporting Excel Charts as Images From a Script or Server
Export charts as PNG or SVG from a script: draw with matplotlib from the same data, render headless with LibreOffice, or use Windows COM.
6 min read
Excel
Building Dashboards in Excel From SQL Output Step by Step
Build an Excel dashboard from SQL output: one data sheet per query, a presentation sheet of tiles and charts, scheduled refresh and tie-out checks.
7 min read
Excel
Sparklines and Conditional Formatting for Quick Scans
Add sparklines, data bars, color scales and icon sets to a table so readers can scan 40 rows in seconds, written from XlsxWriter with accessible choices.
7 min read
Excel
Refreshing Charts From a Changing Data Range in Excel
Fix charts that miss new rows or show blank gaps when data size changes: Excel tables, dynamic named ranges, generated ranges and refresh settings.
7 min read
JSON
Backfilling Historic Events After a Schema Change Safely
Three ways to rewrite a renamed JSON property across 1.5 million events in PostgreSQL: one UPDATE, batches and a table swap, with WAL, bloat and leftovers.
7 min read
JSON
Handling Properties That Change Type in JSON Event Data
Fix invalid input syntax for type numeric on a JSON property that became a string, null or object, with jsonb_typeof, pg_input_is_valid and a function.
7 min read
JSON
Indexing Hot JSON Properties for Dashboards in PostgreSQL
Expression, partial and GIN indexes on a 2.25 million row jsonb event table: a selective lookup fell from 65 ms to 5 ms, a 4 percent filter got slower.
6 min read
JSON
Extracting Properties Into Typed Columns Nightly From JSON
A nightly job that turns jsonb event properties into a typed facts table in PostgreSQL: safe casts, a watermark, idempotent inserts and a 47x speedup.
7 min read
JSON
Designing JSON Event Properties for Analysis From Day One
Four designs for the same 500,000 purchase events compared on size and query time: verbose nesting, short flat keys, hybrid columns and key/value arrays.
6 min read
Excel
Choosing Excel Chart Types for Query Results That Read
Choose an Excel chart type from the shape of your query result: line, column, bar, stacked, scatter, histogram or table, with rules and the mistakes to avoid.
7 min read
ExcelGuide
Charts From Data Pulled Out of Databases Start to Finish
Build clear Excel charts from database data: shape the query, pick the chart, keep ranges live, avoid misleading axes, add sparklines, export images.
17 min read
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