SQL Reference

Tokens

The basic syntactical units of the language are called tokens. A token is a sequence of one or more characters. A token cannot contain blank characters, unless it is a string constant or delimited identifier, which may contain blanks. (These terms are defined later.)

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 under PREPARE.

  Examples 

      ,        'string'        "fld1"        =        .
  

Spaces: A space is a sequence of one or more blank characters. Tokens other than string constants and delimited identifiers must not include a space. Any token may be followed by a space. Every ordinary token must be followed by a space or a delimiter token if allowed by the syntax.

Comments: Static SQL statements may include host language comments or SQL comments. Either type of comment may be specified wherever a space may be specified, except within a delimiter token or between the keywords EXEC and SQL. SQL comments are introduced by two consecutive hyphens (--) and ended by the end of the line. For more information, see SQL Comments.

Uppercase and Lowercase: Any token may include lowercase letters, but a lowercase letter in an ordinary token is folded to uppercase, except for host variables in the C language, which has case-sensitive identifiers. Delimiter tokens are never folded to uppercase. Thus, the statement:

   select * from EMPLOYEE where lastname = 'Smith';

is equivalent, after folding, to:

   SELECT * FROM EMPLOYEE WHERE LASTNAME = 'Smith';

MBCS Considerations

Multi-byte alphabetic letters are not folded to uppercase. Single-byte characters, a to z, are folded to uppercase.