SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 3) ExpressionList (children 1) Function count (children 1) ExpressionList TablesInSelectQuery (children 1) TablesInSelectQueryElement (children 1) TableExpression (children 1) TableIdentifier system.tables Function and (children 1) ExpressionList (children 2) Function equals (children 1) ExpressionList (children 2) Identifier database Function currentDatabase (children 1) ExpressionList Function equals (children 1) ExpressionList (children 2) Identifier name Literal \'join\'