The string operator allows string concatenation with the symbol. All other string manipulation is handled through String functions. For details, see the Functions topic.
By default, the empty string (' ') is interpreted as a single blank in INSERT or assignment statements on varchar data. In concatenating varchar, char, or text data, the empty string is interpreted as a single space. For example, 'abc' + ' ' + 'def' is stored as 'abc def'. The empty string is never evaluated as NULL.