为什么UPPER功能不会改变小写的重音字符

Question

为什么upper()小写重音不会产生任何变化

所以我的州名就像这样翻译

upper('táchira') = 'TáCHIRA'
upper('guárico') = "GUáRICO"

我想

'TÁCHIRA' and 'GUÁRICO'
OR 'TACHIRA' and 'GUARICO'

字段estado是州名

CREATE TABLE mapas.estadosven_region
(
  gid serial NOT NULL,
  geoid double precision,
  estado character varying(80),
  CONSTRAINT estadosven_region_pkey PRIMARY KEY (gid)
)