CreateQuery collapsing (children 3)
 Identifier collapsing
 Columns definition (children 1)
  ExpressionList (children 3)
   ColumnDeclaration key (children 1)
    DataType String
   ColumnDeclaration value (children 1)
    DataType String
   ColumnDeclaration sign (children 1)
    DataType Int8
 Storage definition (children 3)
  Function CollapsingMergeTree (children 1)
   ExpressionList (children 1)
    Identifier sign
  Identifier key
  Set