6. A computer system for managing query creation for querying a database recorded on a physical storage medium with on demand database query reduction by selectively substituting, replacing, and removing specified variables within a sub-query before they are combined into an expanded query, comprising: a query document recorded in computer storage with global variables selectively set off by first tags identifying a first global variable as a complete replacement variable and by second tags identifying a second global variable as a complete removal string, a global variable being a variable which represents a quantity that is available to be modified by a user prior to runtime; a computer run-time agent being a segment of code, separate from a control document, executing in accordance with a first execution schedule, for accessing said control document to generate dynamic content, said control document including a user-adjustable second execution schedule and, responsive to said second execution schedule, said run-time agent determining when to run a query document; and a computer agent for building from said query document an expanded query by replacing any variables set off by said first tags with runtime strings, setting off any unions in said query document; selectively, for each set of second tags, replacing variables in a portion of said string set off by said second tags, or removing said second tags without replacing variables set off by said second tags to restore said portion of said string set off by said second tags to normal syntax, said variables being code definitions of a sub-query that are applied to form a master query and are manipulated by a substitution and replacement strategy to eventually form new content to a coded subquery.
6. A computer system for managing query creation for querying a database recorded on a physical storage medium with on demand database query reduction by selectively substituting, replacing, and removing specified variables within a sub-query before they are combined into an expanded query, comprising: a query document recorded in computer storage with global variables selectively set off by first tags identifying a first global variable as a complete replacement variable and by second tags identifying a second global variable as a complete removal string, a global variable being a variable which represents a quantity that is available to be modified by a user prior to runtime; a computer run-time agent being a segment of code, separate from a control document, executing in accordance with a first execution schedule, for accessing said control document to generate dynamic content, said control document including a user-adjustable second execution schedule and, responsive to said second execution schedule, said run-time agent determining when to run a query document; and a computer agent for building from said query document an expanded query by replacing any variables set off by said first tags with runtime strings, setting off any unions in said query document; selectively, for each set of second tags, replacing variables in a portion of said string set off by said second tags, or removing said second tags without replacing variables set off by said second tags to restore said portion of said string set off by said second tags to normal syntax, said variables being code definitions of a sub-query that are applied to form a master query and are manipulated by a substitution and replacement strategy to eventually form new content to a coded subquery. 7. The computer system of claim 6 , further comprising: said computer agent further for determining if a next given variable changes in each successive union and, if so, removing said second tags to leave this next given variable without replacement; and, if not, replacing said next given variable based on changing selection criteria.