Postgresql Array Functions

When the user defines a data type, the corresponding array type created in the background by the PostgreSQL.

We need to remember that each data type has its corresponding array.

Let us consider a few examples:

• array_append(anyarray, anyelement)

Append an element to the end of an array

For example:

array_append(ARRAY[Sam,Aroni], Tom) 

Result:

{Sam, Aroni, Tom}

• array_cat(anyarray, anyarray)

concatenate two arrays

For example:

array_cat(ARRAY[1,2,3], ARRAY[4,5])

Result:

{1,2,3,4,5}

• array_ndims(anyarray)

returns the number of dimensions of the array

For example:

array_ndims(ARRAY[[1,2,3], [4,5,6]])

Result:

2

• array_length(anyarray, int)

returns the length of the requested array dimension

For example:

array_length(array[1,2,3], 1)

Result:

3