SQL comments

In most host languages, static SQL statements can include host language or SQL comments. In Java™ and REXX, static SQL statements cannot include host language or SQL comments.

Dynamic SQL statements can include SQL comments.

There are two types of SQL comments:

simple comments
Simple comments are introduced by two consecutive hyphens.
bracketed comments
Bracketed comments are introduced by /* and end with */.

These rules apply to the use of simple comments:

  • The two hyphens must be on the same line and must not be separated by a space.
  • Simple comments can be started wherever a space is valid (except within a delimiter token or between 'EXEC' and 'SQL').
  • Simple comments cannot be continued to the next line.
  • In COBOL, the hyphens must be preceded by a space.

These rules apply to the use of bracketed comments:

  • The /* must be on the same line and not separated by a space.
  • The */ must be on the same line and not separated by a space.
  • Bracketed comments can be started wherever a space is valid (except within a delimiter token or between 'EXEC' and 'SQL').
  • Bracketed comments can be continued to the next line.
  • Bracketed comments can be nested within other bracketed comments.

A comment embedded in an SQL statement that precedes a name (such as a table name) may cause object names in the text saved for a view, trigger, variable, or MQT to not be maintained correctly. Similarly, names in rows of a dependency view (such as SYSTRIGDEP) may not be correctly qualified.

Example 1

This example shows how to include simple comments in a statement: 

   CREATE VIEW PRJ_MAXPER         -- PROJECTS WITH MOST SUPPORT PERSONNEL
      AS SELECT PROJNO, PROJNAME  -- NUMBER AND NAME OF PROJECT
         FROM PROJECT
         WHERE DEPTNO = 'E21'     -- SYSTEMS SUPPORT DEPT CODE
         AND PRSTAFF > 1

Example 2

This example shows how to include bracketed comments in a statement: 

   CREATE VIEW PRJ_MAXPER         /* PROJECTS WITH MOST SUPPORT
                                         PERSONNEL                */
      AS SELECT PROJNO, PROJNAME  /* NUMBER AND NAME OF PROJECT   */
         FROM PROJECT
         WHERE DEPTNO = 'E21'     /* SYSTEMS SUPPORT DEPT CODE    */
         AND PRSTAFF > 1