code: func (e *DeleteExec) matchingDeletingTable(tableID int64, col *expression.Column) bool {
  	names, ok := e.tblMap[tableID]
  	if !ok {
  		return false
  	}
  	for _, n := range names {
  		if (col.DBName.L == "" || col.DBName.L == n.Schema.L) && col.TblName.L == n.Name.L {
  			return true
  		}
  	}
  	return false
  }
docs: // matchingDeletingTable checks whether this column is from the table which is in the deleting list.