ms access 中的“LIKE”运算符在 vb.net 中不起作用

Question

I hope someone can shed some light on this strange behavior. I have a very simple sql statement thus:

"SELECT TOP 1 PartRefID FROM Parts WHERE PartDescription LIKE '*Backshell*' AND ParentID = 2097"

which is executed scalar. when I enter this in the access query editor it works just fine and returns the expected value. however, when I run it from within some vb.net code it always returns zero. can anyone tell me why this is the case? thanks

Answer 1

When using .net, you have to use the % sign - it more of a ANSI standard, and this works with jet/ace (access) data engine also.

So, when writing .net code as opposed to VBA, then you are to use % for wild cards - not *. In fact, even in Access VBA, if you were to use ADO (as opposed to the more common and recommended DAO - then even in VBA + ADO, you have to use % in place of *).

so in fact most sql syntax uses %. For ADO, or now what is called ado.net? Then % is to be used.

However, inside access? You can turn on ANSI compatibility - but it WILL make a huge mess of existing access applications - so I don't recommend doing this (enabling Access ANSI sql compatibility mode).

You can quite much assume for "most" software outside of Access - EVEN when hitting the Access database, you use % for wild cards. The only exception here is if one was to use DAO directly as a reference library, and I STRONG recommend you don't do this.

so try using % - and all should be find and well.

Answer 2

尝试替换 *

"SELECT TOP 1 PartRefID FROM Parts WHERE PartDescription LIKE '%Backshell%' AND ParentID = 2097"