String concatenation operators
To concatenate two strings on a single line, use the concatenation operator (two consecutive vertical bars).
	To concatenate two strings on a single line, use the concatenation operator (two consecutive vertical bars).
Syntax
string || string
Parameters
| string | Expression of type CHARorVARCHAR | 
Notes
- || is used to concatenate expressions and constants. The expressions are cast to VARCHARif possible, otherwise toVARBINARY, and must both be one or the other.
- Two consecutive strings within a single SQL statement on separate lines are automatically concatenated
Examples
The following example is a single string written on two lines:
=> SELECT E'xx'-> '\\';
 ?column?
----------
 xx\
(1 row)
The following examples show two strings concatenated:
=> SELECT E'xx' ||-> '\\';
 ?column?
----------
 xx\\
(1 row)
=> SELECT 'auto' || 'mobile';
 ?column?
----------
 automobile
(1 row)
=> SELECT 'auto'-> 'mobile';
 ?column?
----------
 automobile
(1 row)
=> SELECT 1 || 2;
 ?column?
----------
 12
(1 row)
=> SELECT '1' || '2';
 ?column?
----------
 12
(1 row)
=> SELECT '1'-> '2';
 ?column?
----------
 12
(1 row)