Give alias / column definition list to ROWS FROM()

Question

This obviously doesn't work:

SELECT regexp_matches[1], regexp_matches[1]
FROM ROWS FROM (
  regexp_matches('fooBarBaz', '[[:upper:]]', 'g'),
  regexp_matches('fooBarBaz', '[[:lower:]]', 'g')
);

Error: [42702] column reference "regexp_matches" is ambiguous

How can I give an alias to the function calls?

SELECT u[1], l[1]
FROM ROWS FROM (
  regexp_matches('fooBarBaz', '[[:upper:]]', 'g'),
  regexp_matches('fooBarBaz', '[[:lower:]]', 'g')
) AS (u text[], l text[]);

Error: [42601] ROWS FROM() with multiple functions cannot have a column definition list
Hint: Put a separate column definition list for each function inside ROWS FROM().

SELECT u[1], l[1]
FROM ROWS FROM (
  regexp_matches('fooBarBaz', '[[:upper:]]', 'g') AS (u text[]),
  regexp_matches('fooBarBaz', '[[:lower:]]', 'g') AS (l text[])
);

Error: [42601] a column definition list is only allowed for functions returning "record"

I'm out of ideas. This has to be possible.

Documentation:

• Syntax of ROWS FROM() (7.2.1.4. Table Functions)
• regexp_matches returns setof text[] (Table 9.9. Other String Functions)

Answer 1

You need a table alias too

SELECT T.u[1], t.l[1]
FROM ROWS FROM (
  regexp_matches('fooBarBaz', '[[:upper:]]', 'g'),
  regexp_matches('fooBarBaz', '[[:lower:]]', 'g')
) AS t (u, l);