CreateQuery test_table (children 3)
 Identifier test_table
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration A (children 1)
    DataType Nullable (children 1)
     ExpressionList (children 1)
      DataType String
   ColumnDeclaration B (children 1)
    DataType Nullable (children 1)
     ExpressionList (children 1)
      DataType String
 Storage definition (children 3)
  Function MergeTree
  Function tuple (children 1)
   ExpressionList (children 2)
    Identifier A
    Identifier B
  Set
