text.out

来自「postgresql8.3.4源码,开源数据库」· OUT 代码 · 共 54 行

--
-- TEXT
--
SELECT text 'this is a text string' = text 'this is a text string' AS true;
 true 
------
 t
(1 row)

SELECT text 'this is a text string' = text 'this is a text strin' AS false;
 false 
-------
 f
(1 row)

CREATE TABLE TEXT_TBL (f1 text);
INSERT INTO TEXT_TBL VALUES ('doh!');
INSERT INTO TEXT_TBL VALUES ('hi de ho neighbor');
SELECT '' AS two, * FROM TEXT_TBL;
 two |        f1         
-----+-------------------
     | doh!
     | hi de ho neighbor
(2 rows)

-- As of 8.3 we have removed most implicit casts to text, so that for example
-- this no longer works:
select length(42);
ERROR:  function length(integer) does not exist
LINE 1: select length(42);
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
-- But as a special exception for usability's sake, we still allow implicit
-- casting to text in concatenations, so long as the other input is text or
-- an unknown literal.  So these work:
select 'four: '::text || 2+2;
 ?column? 
----------
 four: 4
(1 row)

select 'four: ' || 2+2;
 ?column? 
----------
 four: 4
(1 row)

-- but not this:
select 3 || 4.0;
ERROR:  operator does not exist: integer || numeric
LINE 1: select 3 || 4.0;
                 ^
HINT:  No operator matches the given name and argument type(s). You might need to add explicit type casts.