How to concatenate all results from table row?

问题

Can not find a solution to do something like:

SELECT CONCAT_WS(',', (
    SELECT * FROM table WHERE id = 1
))

How can I do that in PostgreSQL?

回答1:

Quick and dirty:

SELECT t::text FROM tbl t WHERE id = 1;

• t is an alias for the table and not strictly needed. You can use the original table name as well. But if you have a column of the same name it takes precedence.

• So t represents the row type of the table, which is automatically coerced to text representation on output.
  I added an explicit cast to make it text internally as well - in case you want to do anything with it ...
  t::text is Postgres short notation for the SQL standard cast (t AS text), which you can use as well. Details in the manual.

• You may want to trim the (single!) leading and trailing parentheses that denote a row type:

  SELECT right(left(t::text, -1), -1))
  FROM   tbl AS t
  WHERE  id = 1;
  

• "dirty", becaue you get Postgres row notation, the separator happens to be just the comma you asked for, but some values are also escaped and / or double quoted if needed.

来源：https://stackoverflow.com/questions/23918283/how-to-concatenate-all-results-from-table-row