The following query is blocking the complete TempDB (before Version 2014) on a SQL Server until the Statement finished:
Select * INTO #TempTable From [Table,JoinedTables]
In a compliant way it would look like:
Create Table #TempTable ( -- Table definition ) Insert Into #TempTable ( -- ColumnList ) VALUES () or SELECT (ColumnList) FROM [Tables]
It might cause some performance issue or is at least a bad code smell and is at least related to code smells.