PostgreSQL varchar[] 数组类型操作

PostgreSQL varchar[] 数组类型操作：

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
@>	contains	ARRAY[1,4,3] @> ARRAY[3,1]	t
<@	is contained by	ARRAY[2,7] <@ ARRAY[1,7,4,2,6]	t
&&	overlap (have elements in common)	ARRAY[1,4,3] && ARRAY[2,1]	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}