| SQL functionsPostgres builtin functions and operators (a sample)String
 
  
    | Function | Description | Example | Result |  
          | || | Concatenation | 'abc' || 'def' | 'abcdef' |  
          | char_length(s) | Number of characters in string | char_length('SQL') | 3 |  
          | postion(s in t) | Postion of s in t, (1-based) | position('y' in 'MySQL') | 2 |  
          | substr(string, from[, count]) | Extract substring, (1-based) | substr('PostgreSQL', 8) | SQL |  |