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SQL programmingYou can use the HCL OneDB™ implementation of the SQL language to develop applications for HCL OneDB™ database servers.
Guide to SQL: SyntaxThe HCL OneDB™ Guide to SQL: Syntax describes the syntax of the statements, data types, expressions, operators, and built-in functions of the HCL OneDB™ dialect of the SQL language.
SQL statementsThis chapter describes the syntax and semantics of SQL statements that are recognized by HCL OneDB™.
SELECT statementUse the SELECT statement to retrieve values from a database or from an SPL or collection variable. A SELECT operation is called a query.
Projection ClauseThe Projection clause (sometimes called the Select clause) specifies a list of database objects or expressions to retrieve, and can set restrictions on qualifying rows. (The select list is sometimes also called the projection list.)
Declaring a Display Label

Declaring a Display Label

You can declare a display label for any column or column expression in the select list of the Projection clause. This temporary name is in scope only while the SELECT statement is executing.

In DB-Access, a display label appears as the heading for that column in the output of the SELECT statement.

In , the value of display_label is stored in the sqlname field of the sqlda structure. For more information on the sqlda structure, see the HCL OneDB™ ESQL/C Programmer's Manual.

If your display label is an SQL keyword, use the AS keyword to clarify the syntax. For example, to use UNITS, YEAR, MONTH, DAY, HOUR, MINUTE, SECOND, or FRACTION as display labels, use the AS keyword with the display label. The following statement uses AS with minute as a display label:

SELECT call_dtime AS minute FROM cust_calls;

For the keywords of SQL, see Keywords of SQL for HCL OneDB.

If you use the INTO Table clause to create a temporary or permanent table to store the query results, you must declare a display label for any database object or expression in the select list that is not a simple column expression. The display label is used as the name of the column in the temporary or permanent table.

If you are using the SELECT statement to define a view, do not use display labels. Specify the desired label names in the CREATE VIEW column list instead.