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Table 9-41 shows the operators available for array types.
Table 9-41. array Operators
| Operator | Description | Example | Result |
|---|---|---|---|
| = | equal | ARRAY[1.1,2.1,3.1]::int[] = ARRAY[1,2,3] | t |
| <> | not equal | ARRAY[1,2,3] <> ARRAY[1,2,4] | t |
| < | less than | ARRAY[1,2,3] < ARRAY[1,2,4] | t |
| > | greater than | ARRAY[1,4,3] > ARRAY[1,2,4] | t |
| <= | less than or equal | ARRAY[1,2,3] <= ARRAY[1,2,3] | t |
| >= | greater than or equal | ARRAY[1,4,3] >= ARRAY[1,4,3] | t |
| || | array-to-array concatenation | ARRAY[1,2,3] || ARRAY[4,5,6] | {1,2,3,4,5,6} |
| || | array-to-array concatenation | ARRAY[1,2,3] || ARRAY[[4,5,6],[7,8,9]] | {{1,2,3},{4,5,6},{7,8,9}} |
| || | element-to-array concatenation | 3 || ARRAY[4,5,6] | {3,4,5,6} |
| || | array-to-element concatenation | ARRAY[4,5,6] || 7 | {4,5,6,7} |
See Section 8.10 for more details about array operator behavior.
Table 9-42 shows the functions available for use with array types. See Section 8.10 for more discussion and examples for the use of these functions.
Table 9-42. array Functions
| Function | Return Type | Description | Example | Result |
|---|---|---|---|---|
array_cat (anyarray, anyarray) |
anyarray | concatenate two arrays, returning NULL for NULL inputs | array_cat(ARRAY[1,2,3], ARRAY[4,5]) | {1,2,3,4,5} |
array_append (anyarray, anyelement) |
anyarray | append an element to the end of an array, returning NULL for NULL inputs | array_append(ARRAY[1,2], 3) | {1,2,3} |
array_prepend (anyelement, anyarray) |
anyarray | append an element to the beginning of an array, returning NULL for NULL inputs | array_prepend(1, ARRAY[2,3]) | {1,2,3} |
array_dims (anyarray) |
text | returns a text representation of array dimension lower and upper bounds, generating an ERROR for NULL inputs | array_dims(array[[1,2,3], [4,5,6]]) | [1:2][1:3] |
array_lower (anyarray, integer) |
integer | returns lower bound of the requested array dimension, returning NULL for NULL inputs | array_lower(array_prepend(0, ARRAY[1,2,3]), 1) | 0 |
array_upper (anyarray, integer) |
integer | returns upper bound of the requested array dimension, returning NULL for NULL inputs | array_upper(ARRAY[1,2,3,4], 1) | 4 |
array_to_string (anyarray, text) |
text | concatenates array elements using provided delimiter, returning NULL for NULL inputs | array_to_string(array[1, 2, 3], '~^~') | 1~^~2~^~3 |
string_to_array (text, text) |
text[] | splits string into array elements using provided delimiter, returning NULL for NULL inputs | string_to_array( 'xx~^~yy~^~zz', '~^~') | {xx,yy,zz} |