请教，怎样写才是效率最好的？
因为dmax函数在未找到满足条件的数值时会返回null,
所以下面这样的写法1:会出错
dim lgIDtst as long

写法1:
lgIDtst = Dmax("[ID]", strMyTable, "ID LIKE '" & me.IDinputed & "*'")

以下的这种写法2 可以， 但是会把dmax函数执行两遍，影响了效率，

写法2:
if isnull(Dmax("[ID]", strMyTable, "ID LIKE '" & me.IDinputed & "*'")) then
...
else
lgIDtst = Dmax("[ID]", strMyTable, "ID LIKE '" & me.IDinputed & "*'")
...
end if

请问怎样的写法最为高效合理?

[解决办法]
lgIDtst = nz(Dmax("[ID]", strMyTable, "ID LIKE '" & me.IDinputed & "*'"),0)
[解决办法]
lgIDtst = NZ(Dmax("[ID]", strMyTable, "ID LIKE '" & me.IDinputed & "*'"))