Text concatenation

{text,ttext} || {text,ttext} → ttext

SELECT ttext '[AA@2001-01-01, AA@2001-01-04)' || text 'B';
-- ["AAB"@2001-01-01, "AAB"@2001-01-04)
SELECT ttext '[AA@2001-01-01, AA@2001-01-04)' || ttext '[BB@2001-01-02, BB@2001-01-05)';
-- ["AABB"@2001-01-02, "AABB"@2001-01-04)
SELECT ttext '[A@2001-01-01, B@2001-01-03, C@2001-01-04]' ||
  ttext '{[D@2001-01-01, D@2001-01-02), [E@2001-01-02, E@2001-01-04)}';
-- {["AD"@2001-01-01, "AE"@2001-01-02, "BE"@2001-01-03, "BE"@2001-01-04)}

Transform in lowercase, uppercase, or initcap

upper(ttext) → ttext

lower(ttext) → ttext

initcap(ttext) → ttext

SELECT lower(ttext '[AA@2001-01-01, bb@2001-01-02]');
-- ["aa"@2001-01-01, "bb"@2001-01-02]
SELECT upper(ttext '[AA@2001-01-01, bb@2001-01-02]');
-- ["AA"@2001-01-01, "BB"@2001-01-02]
SELECT initcap(ttext '[AA@2001-01-01, bb@2001-01-02]');
-- ["Aa"@2001-01-01, "Bb"@2001-01-02]