SPQuery is not working properly, its throwing following exception.
"One or more field types are not installed properly. Go to the list settings page to delete these fields."
Please check the code snippet below:
SPSite spsite = new SPSite("siteurl");
SPWeb site = spsite.OpenWeb();
SPList list = site.Lists["listname"];
SPQuery query = new SPQuery();
query.Query = "<Where><Eq><FieldRef Name='ServiceLevel'/><Value Type='String'>345</Value></Eq></Where>";
SPListItemCollection items = list.GetItems(query);