How can I filter dates to one month without relying on ambiguous date text?

In SQLite, if the column contains valid date-only text consistently formatted as zero-padded YYYY-MM-DD, compare it with the month’s first day and the first day of the next month. For March 2025:

SELECT sale_date, amount
FROM sales
WHERE sale_date >= '2025-03-01'
  AND sale_date <  '2025-04-01';

The lower bound is inclusive, so March 1 qualifies. The upper bound is exclusive, so April 1 does not. With fixed-width ISO date strings, SQLite’s text ordering follows chronological order for this representation. [S1][S2]

Assume these are valid date-only strings in a SQLite TEXT column. For the March 2025 query:

• 2025-02-28 — excluded, because it is before the start.
• 2025-03-01 — included, because it equals the inclusive start.
• 2025-03-15 — included, because it is within the range.
• 2025-03-31 — included, because it is before the upper boundary.
• 2025-04-01 — excluded, because it equals the exclusive end.

The last row shows why the condition is < '2025-04-01', rather than <= '2025-04-01'. This comparison relies on valid, consistent, fixed-width ISO date-only text; it does not establish correct results for mixed formats or malformed values. [S1][S2]

The half-open range states the month’s boundary directly: include values at or after March 1, and exclude values at or after April 1. That gives March 31 a clear position inside the range and April 1 a clear position outside it, without needing to find the final calendar day when setting the endpoint. For this date-only text example, March 31 is less than April 1, so it qualifies. [S1]

Keep the scope in mind: this example is for consistently formatted date-only text. The cited guidance does not establish that the same string comparison handles timestamp values, timezone-bearing values, or mixed representations correctly. [S1][S2]

Confirm that you are using SQLite and inspect representative stored values in the column. This pattern depends on valid values consistently written as zero-padded YYYY-MM-DD text. If values instead include formats such as 03/04/2025, omit leading zeroes, contain timestamps, or are malformed, this example does not establish that the comparison will order or filter them correctly. [S1][S2]

For another month, set the inclusive lower boundary to that month’s first day and the exclusive upper boundary to the following month’s first day. For example, a February range ends at March 1, not at a date inside February. Check the first day, last day, and following month’s first day when reviewing the result. The sample dates here are illustrative, not records from a real database.