sometimes, the index u created in table maybe invaild and cause the problem in query the data of table, for example:
1.”select * from tb” will export the all the data of tb
2. “select * from tb where id=’222′” will hang there and no data exported,there is the index created in colume “id”
most of time, it’s the invaild of index index_name created in id colume which case the situation,just follow this maybe help
“ALTER INDEX index_name REBUILD”..