On Thu, 2025-04-03 at 18:22 +0000, PG Doc comments form wrote: > Page: https://www.postgresql.org/docs/17/sql-expressions.html > Description: > > I skimmed over section 4.2 while waiting for a meeting to start and found no > mention of the following two questions that immediately pop up in my mind > when subscripts are mentionned: > > Are subscripts 0-based or 1-based?
This question is answered in the documentation of the array data types: https://www.postgresql.org/docs/current/arrays.html The array subscript numbers are written within square brackets. By default PostgreSQL uses a one-based numbering convention for arrays, that is, an array of n elements starts with array[1] and ends with array[n]. > Are slice boundaries inclusive or exclusive? That becomes clear on the same page: We can also access arbitrary rectangular slices of an array, or subarrays. An array slice is denoted by writing lower-bound:upper-bound for one or more array dimensions. For example, this query retrieves the first item on Bill's schedule for the first two days of the week: SELECT schedule[1:2][1:1] FROM sal_emp WHERE name = 'Bill'; schedule ------------------------ {{meeting},{training}} (1 row) Admittedly, there is no exact definition, but the example makes clear that the boundaries are inclusive. I don't think that we need to repeat that information. Yours, Laurenz Albe
