Hologres is compatible with PostgreSQL and allows you to use standard PostgreSQL syntax for data development.

The following table describes the array functions that are supported by Hologres. Hologres supports a subset of PostgreSQL functions. For information about how to use the following array functions, see Array Functions and Operators.
Function Description Example Result
array_append(anyarray, anyelement) Appends an element to the end of an array. array_append(ARRAY[1,2], 3) {1,2,3}
array_cat(anyarray,anyarray) Concatenates two arrays. array_cat(ARRAY[1,2,3], ARRAY[4,5]) {1,2,3,4,5}
array_ndims(anyarray) Returns the number of dimensions of an array. array_ndims(ARRAY[[1,2,3], [4,5,6]]) 2
array_dims(anyarray) Returns a text representation of the dimensions of an array. array_dims(ARRAY[[1,2,3], [4,5,6]]) [1:2][1:3]
array_length(anyarray, int) Returns the length of the requested array dimension. array_length(array[1,2,3], 1) 3
array_lower(anyarray, int) Returns the lower bound of the requested array dimension. array_lower('[0:2]={1,2,3}'::int[], 1) 0
array_positions(anyarray, anyelement) Returns an array of subscripts of all occurrences of the second argument in the array given as the first argument. The array given as the first argument must be one-dimensional. array_positions(ARRAY['A','A','B','A'], 'A') {1,2,4}
array_prepend(anyelement, anyarray) Prepends an element to the start of an array. array_prepend(1, ARRAY[2,3]) {1,2,3}
array_remove(anyarray, anyelement) Removes all elements that are equal to the given value from an array. array_remove(ARRAY[1,2,3,2], 2) {1,3}
array_to_string(anyarray,text[,text]) Concatenates array elements by using a specified delimiter and an optional null string. array_to_string(ARRAY[1, 2, 3, NULL, 5], ',', '*') 1,2,3,*,5
array_upper(anyarray, int) Returns the upper bound of the requested array dimension. array_upper(ARRAY[1,8,3,7], 1) 4
unnest(anyarray) Expands an array to a set of rows. unnest(ARRAY[1,2])



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