mi_qual_constisnull

The mi_qual_constisnull_nohostvar() function evaluates the explicit value, if any, that the WHERE clause specifies in the function argument list. This function does not evaluate host variables. Call this function from the am_scancost purpose function.

The following functions compare a column that contains a row to a row constant. Each function depends on a client application to provide part or all of the constant value. The Return Value column shows the results of the mi_qual_constisnull_nohostvar() function.

Sample Function	Description	Return Value
function(column, row(10,?,20))	The row contains the explicit constant values 10 and 20. The unknown value that replaces ? does not influence the return value of mi_qual_constisnull_nohostvar().	MI_FALSE
function(column, row(NULL,?,20))	The first field in the row constant specifies an explicit NULL value.	MI_TRUE
function(column,?)	The arguments to the function contain no explicit values. The qualification descriptor contains a NULL in place of the missing explicit value.	MI_TRUE

Return Values

MI_TRUE indicates one of the following conditions in the argument list:

An explicit NULL-valued constant
No explicit values

MI_FALSE indicates that the constant argument is not NULL-valued.

mi_qual_constisnull_nohostvar()

Syntax

Usage

Return Values

Related Topics