There are three ways depending on how (if at all) the two tables are interelated.
1. Continuous columns from one table to the next
Meaning: you get the side-by-side effect, with headers and footers appearing correctly at the top of both tables sitting next to each other, but the pair are one continuous table split across two columns, so you can select cells down the columns in both halves at once, paste data into both at once, etc (rather than being one table, then another, extra table).
Probably the simplest way is with two linked frames and a frame break pushing the second half of the table into the second frame (steps below).
- Set up your table in a text frame in the left position. Make any rows you want to be above / below both sides set as Header / Footer rows (using
Table > Convert Rows while they're selected)
- Set up the table as one long table, with the rows you want to be on the right below the rows you want on the left (one header / footer for the whole two-tables-combined). If you need it the other way round, top on the right, that's fine too, just move this first table to the right.
- Click the 'Out' port in the bottom right end of the table's text frame to create a second linked frame that excess rows can overspill into. Place it to the right of your table as desired.
- Put the cursor in the start of the first row that you want to be in the right-hand section of the table, and insert a frame break (
Type > Insert break character > Frame break, or
shift+enter), sending it to the second frame.
- If you need these two tables to sit side-by-side in the main body text, so they move as the text changes, see 3. below.
If you want it to flow from one to the other so that when you delete one row on the left, another row moves to replace it from the right, don't add the frame break and instead just shrink down the text frame until half the table is pushed into the second frame.
2. Different columns, continuous rows
This is assuming you want continuous columns. If what you actually want is left and right tables with different columns but the same row headings, lined up horizontally, just make one wide table with extra columns on the left and include a blank column - no fill, no stroke other than sides if needed, no content, etc - to make the 'gap' between left and right.
3. Separate tables, sitting in the same position in the main body text
(just re-read the question: I think this might be what you mean but I don't see where the 'extra' table would come from)
If they really are completely separate tables (or split into separate frames), and you've got a two column layout and you simply want to put them into the layout so one is after the other in the document flow but fixed to the right instead of dropping below, you can do that while keeping the tables within the flow of the text, by nesting a text frame in the main text frame:
- Create a text frame a bit taller than the taller of the two tables, and as wide as the two columns.
- Create a text frame the size of the right table, cut and paste the right table into it.
- Cut it, put the type cursor in the wide frame, and paste it (so it's inline with the text). Use the type tool to select this nested table frame like it was text.
- Set it to right align. It should jump to the right of the frame.
- Do the same with the left table, but keep it as left aligned. You've now got the two tables side by side in a frame. (if ever need more than two, you can have them all on one line and place them using tabs and the
Type > Tabs window)
- Select this text frame, cut it, put the Type cursor in the position in your main body text where you want the side-by-side tables, and paste.
- It's probably sitting on top of text in the right hand column. Select the frame, and in the Text Wrap window (
Window > Text Wrap), set it to "Wrap around bounding box" (second icon) so that it pushes the text in the opposing column out the way.
You've now got two tables that are fixed to be side by side, and are sat in a set position in the flow of your document and will move with that position as the document text changes.
Don't forget to keep an eye on it to make sure it doesn't end up in the wrong column or in an awkward position on the page.