Constants can be embedded within a SELECT statement. This feature can be used with an interactive SQL environment to produce simple reports. The ANSI/ISO standard specifies that SQL constants be enclosed in single quotes (‘…’). If a single quote is to be included in the constant text, it is written within the constant as two consecutive single-quote characters (‘It”s done’). Some SQL products such as Informix and SQL Server use constants enclosed in double quotes (“…”). Other SQL engines may have difficulty with the double quote character.

SELECT 'constant1', column1,
       'constant2', column2, ...
  FROM table1, table2, ...;

Notes:

> Constant values are enclosed within quotes and “nested” within column names of the
SELECT statement.

> The constant values are positional and repeated within each row that is returned.