The following table lists descriptions of C language style comments supported in Teradata MultiLoad.
| Comment Topic | Description |
|---|---|
| Beginning and Ending Delimiters | A comment begins with a slash-asterisk (/*) character sequence and ends with an asterisk-slash (*/) sequence. All intervening text is treated as a comment. |
| Comment Destinations | Comments are always written to the message destination and they may or may not be sent to Teradata Database. Comments that are followed by a semicolon character are considered to be stand alone: /*Comment text*/; CREATE TABLE table1(f1 INTEGER); In this case, the comment is not associated with the SELECT statement and is not sent to Teradata Database. Comments that are not followed by a semicolon character are considered to be part of the following command or statement: /*Comment text*/ CREATE TABLE table1(f1 INTEGER); In this case, the comment is associated with the SELECT statement and is sent to Teradata Database. |
| Invalid Within String or Character Literals | Comments cannot occur within string or character literals. A /* within a quoted string is not treated as the beginning of a comment. |
| Nested Comments | Teradata MultiLoad supports nested comments, but Teradata Database does not. Always delimit nested comments with a semicolon character. If a semicolon is not used to delimit a nested comment, it is considered to be part of the current command or statement. If that happens to be a Teradata SQL statement, it is sent to Teradata Database, producing a syntax error. |
| Using Comments With Teradata SQL Statements | If a comment with a Teradata SQL statement is used, add a semicolon to the end of the comment if the comment should not be sent to Teradata Database. If a semicolon is not used, Teradata MultiLoad sends the comment to Teradata Database along with the Teradata SQL statement. |
| Variable Substitution | Substitution of values for variable names continues within comments. Use two ampersand characters (&&) when the variable name is required. |