return nil, errIncorrectSQLFunctionArgumentType(err)
	}

	// Assemble other arguments
	arg2, arg3 := e.From, e.For
	// Check if the second form of substring is being used
	if e.From == nil {
		arg2, arg3 = e.Arg2, e.Arg3
	}

	// Evaluate the FROM argument
	v2, err := arg2.evalNode(r, tableAlias)
	if err != nil {
		return nil, err
	}
	inferTypeForArithOp(v2)

type SubstringFunc struct {
	Expr *PrimaryTerm `parser:" \"SUBSTRING\" \"(\" @@ "`
	From *Operand     `parser:" ( \"FROM\" @@ "`
	For  *Operand     `parser:"   (\"FOR\" @@)? \")\" "`
	Arg2 *Operand     `parser:" | \",\" @@ "`
	Arg3 *Operand     `parser:"   (\",\" @@)? \")\" )"`
}

// ExtractFunc represents EXTRACT sql function
type ExtractFunc struct {

	ReplicationStatusInternal string                 // stringified representation of all replication activity
	// VersionPurgeStatusInternal is internally in the format "arn1=PENDING;arn2=COMPLETED;"
	VersionPurgeStatusInternal string                            // stringified representation of all version purge statuses