Tokens

The basic syntactical units of the SQL language are called tokens. A token consists of one or more characters of which none are blanks, control characters, or characters within a string constant or delimited identifier.

Tokens are classified as ordinary or delimiter tokens:

An ordinary token is a numeric constant, an ordinary identifier, a host identifier, or a keyword.
Examples:
```
    1        .1        +2        SELECT        E        3
```
A delimiter token is a string constant, a delimited identifier, an operator symbol, or any of the special characters shown in the syntax diagrams. A question mark (?) is also a delimiter token when it serves as a parameter marker, as explained in PREPARE.
Examples:
```
    ,        'string'        "fld1"        =        .
```

Spaces

A space is a sequence of one or more blank characters.

Uppercase and lowercase

A token in an SQL statement can include lowercase letters, but lowercase letters in an ordinary token are folded to uppercase. Delimiter tokens are never folded to uppercase.

Example: The following two statements, after folding, are equivalent:

   select * from PCB01.HOSPITAL where hospname = 'Alexandria';

   SELECT * FROM PCB01.HOSPITAL WHERE HOSPNAME = 'Alexandria';