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Some data sources don’t come with a fixed date column. For those, Adriel needs to know which column holds the date and how that column writes its dates. Dashboard date ranges use this setting to filter rows. This article lists the date formats those data sources accept and explains how to read and enter them.
This article applies only to the following data sources: Google Sheets, CSV Files, Amazon S3, File from Email, File from OneDrive, File from SFTP, Google BigQuery, MySQL, Postgres, Redshift, Snowflake, and MongoDB.All other data sources, such as ad platforms and analytics tools, provide their own dates. They need no date format setup, and nothing on this page applies to them.

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How the date field works

After one of these data sources is created, its date column is chosen in the data source’s settings: under Select a date dimension, pick the column in Dimension. Adriel then checks that column’s values and fills in Format automatically. Detection succeeds only when the column’s values match one of the supported formats listed below. The list is strict. It is not a set of examples. A date written any other way fails, even if it looks like an ordinary date. If a column’s dates are not in a supported format, the fix is to change how the dates are written in the source data. Typing a different format string does not help. Change the column in the sheet, file, or database table to one of the supported formats, then refresh the data source.

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Reading a date format

A date format is a pattern of letters that describes how each part of a date is written. These patterns follow the date-fns format reference, which covers every possible token. In practice, only the tokens below appear in the supported formats. Everything else in a format, such as -, /, ., ,, and spaces, must appear in the data exactly as written.
Tokens are case-sensitive. Capital MM means month and lowercase mm means minutes. A format written as mm/dd/yyyy reads the middle of 06/25/2026 as minutes instead of a month, so the dates come out wrong or fail. Always use capital M for months and lowercase y and d for years and days.

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ISO dates

ISO 8601 is an international standard for writing dates, ordered from the largest unit to the smallest: year, month, day. A plain ISO date looks like 2026-06-25. An ISO date with a time adds a T followed by the time, and it can end with a time zone, for example 2026-06-25T14:30:00Z. ISO is the safest choice when the date format of the source data can be picked freely. The order is never ambiguous, most spreadsheet tools and databases can export it, and it is always supported.

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Unix timestamps

A Unix timestamp stores a moment in time as a single number: the time elapsed since 1 January 1970 (UTC). Two variants are supported:
  • Seconds — usually 10 digits, for example 1782345600.
  • Milliseconds — usually 13 digits, for example 1782345600000.
Both examples above represent 25 June 2026, 00:00 UTC.

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Supported date formats

The date field’s values must match one of the formats below exactly, including separators and spacing. Every example shows 25 June 2026.

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Standard formats

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Year first

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Month first

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Day first

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Month names

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Year and month only, or month only

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Correcting a detected format

Occasionally a column matches more than one supported format, and the detected format reads the dates the wrong way. For example, 06/05/2026 fits both MM/dd/yyyy (5 June) and dd/MM/yyyy (6 May). In that case, edit Format under Select a date dimension in the data source’s settings so it matches how the source data writes dates. Check that months use capital MM and not lowercase mm. Editing the format only changes how a supported format is read. It does not make an unsupported format work. A column whose values match none of the supported formats fails whatever format is entered, so the only fix is to rewrite the column in the source data. ISO (2026-06-25) is the safest target. Keep every row in the date column in the same format. A single row written differently can stop the sync.

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Troubleshooting

The column’s values do not match any supported format. Compare a few values against the supported formats, including separators, spaces, and trailing periods. Then change the column in the source data to a supported format, such as ISO (2026-06-25), and refresh the data source.
At least one value in the date column does not match the chosen format. The error names the first value that failed. Correct that value, and any others written differently, in the source data. Check that the rest of the column uses the same format.
Either the format uses lowercase mm (minutes) where it should use capital MM (month), or the day and month are swapped. For example, 06/05/2026 reads as 5 June with MM/dd/yyyy and as 6 May with dd/MM/yyyy. Pick the format that matches how the source data writes dates.
No date field is set for the data source, so Adriel treats all rows as one snapshot. In the data source’s settings, under Select a date dimension, choose the date column in Dimension.

How to connect Google Sheets

Connect a spreadsheet tab and choose its date column.

How to connect CSV Files

Upload CSV or XLSX files as a data source.

Column type mismatch

General checks for sync failures caused by column values.

Data blending

Combine file and database data with ad platform data.