Concatenate two tables along the columns. The total number of columns will be the sum of the two tables. The total number of rows will depend if the two table have common rows (based on name). If the two table have the same row (based on name), the values of theses rows are concatenated starting from the first table into the same row.

If a row doesn't exist in the other table, it will be concatenate with value provided in fill_nan.

Concatenate two tables along the rows. The total number of rows will be the sum of the two tables. The total number of columns will depend if the two table have common columns (based on name). If the two table have the same column (based on name), the values of theses columns are concatenated starting from the first table into the same column.

If a column doesn't exist in the other table, it will be concatenate with value provided in fill_nan.