Global Functions
The DB Interface Module provides a predefined set of global functions, which allow an application to build portable SQL expressions.
Table 4 lists restrictions on the global functions associated with RWDBExpr.
Table 4 – Restrictions on the use of global functions with RWDBExpr 
Function
Restrictions
rwdbAvg(const RWDBExpr&)
None. Corresponds to: AVG(expr)
rwdbCast(const RWDBExpr&,
const RWDBValue&)
None. Corresponds to: {fn CONVERT(expr, value)}
rwdbCast(const RWDBExpr&,
const RWDBValue&,
const RWDBExpr&)
Same as the two-expression form, as MySQL does not support this form.
rwdbCast(const RWDBExpr&,
const RWDBValue&,
const RWDBExpr&,
const RWDBExpr&)
Same as the two-expression form, as MySQL does not support this form.
rwdbCharLength(const RWDBExpr&)
None. Corresponds to: {fn LENGTH(expr)}
rwdbCount()
None. Corresponds to: COUNT(*)
rwdbCount(const RWDBExpr&)
None. Corresponds to: COUNT(expr)
rwdbCountDistinct(const RWDBExpr&)
None. Corresponds to: COUNT(DISTINCT expr)
rwdbCurrentUser()
None. Corresponds to: CURRENT_USER()
rwdbExists(const RWDBSelectorBase&)
None. Corresponds to: EXISTS(sel)
rwdbLower(const RWDBExpr&)
None. Corresponds to: {fn LCASE(expr)}
rwdbMax(const RWDBExpr&)
None. Corresponds to: MAX(expr)
rwdbMin(const RWDBExpr&)
None. Corresponds to: MIN(expr)
rwdbName(const RWCString&,
const RWDBExpr&)
None. Corresponds to: expr AS str
rwdbPosition(const RWDBExpr&,
const RWDBExpr&)
None. Corresponds to: {fn LOCATE(expr0, expr1)}
rwdbSessionUser()
None. Corresponds to: SESSION_USER()
rwdbSubString(const RWDBExpr&,
const RWDBExpr&)
None. Corresponds to: {fn SUBSTRING(expr0, expr1, LENGTH(expr0))}
rwdbSubString(const RWDBExpr&,
const RWDBExpr&,
const RWDBExpr&)
None. Corresponds to: {fn SUBSTRING(expr0, expr1, expr2)}
rwdbSum(const RWDBExpr&)
None. Corresponds to: SUM(expr)
rwdbSystemDateTime()
None. Corresponds to: {fn NOW()}
rwdbSystemUser()
None. Corresponds to: SYSTEM_USER()
rwdbTrimLeading(const RWDBExpr&,
const RWDBExpr&)
None. Corresponds to: TRIM(LEADING expr0 FROM expr1)
rwdbTrimTrailing(const RWDBExpr&,
const RWDBExpr&)
None. Corresponds to: TRIM(TRAILING expr0 FROM expr1)
rwdbTrimBoth(const RWDBExpr&,
const RWDBExpr&)
None. Corresponds to: TRIM(BOTH expr0 FROM expr1)
rwdbUpper(const RWDBExpr&)
None. Corresponds to: {fn UCASE(expr)}