Update

With the addition of the code I can see exatly what you mean. Similar to my inelegant hack below. Thanks++

I may be being obtuse but I don't quite see how. Essentially we have to 'join' the two tables so we can sum the counts (ie b occurs with a count of 1 in each of the original tables so need to have a count of 2 in the final table, whereas a and c retain their counts of 1)

With a merge we will just get 2 rows of b.

This works (it is a kind of a merge) but is not very efficient:

mysql> select * from tok1;
+-------+-------+
| token | count |
+-------+-------+
| a     |     1 |
| b     |     2 |
+-------+-------+
2 rows in set (0.00 sec)

mysql> select * from tok2;
+-------+-------+
| token | count |
+-------+-------+
| b     |     1 |
| c     |     4 |
+-------+-------+
2 rows in set (0.00 sec)

mysql>  insert into all_tok select token,count,0 from tok1 union selec
+t token,0,count from tok2;
Query OK, 4 rows affected (0.01 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> select * from all_tok;
+-------+--------+--------+
| token | count1 | count2 |
+-------+--------+--------+
| a     |      1 |      0 |
| b     |      2 |      0 |
| b     |      0 |      1 |
| c     |      0 |      4 |
+-------+--------+--------+
4 rows in set (0.00 sec)

mysql> select token,sum(count1+count2) from all_tok group by token;
+-------+--------------------+
| token | sum(count1+count2) |
+-------+--------------------+
| a     |                  1 |
| b     |                  3 |
| c     |                  4 |
+-------+--------------------+
3 rows in set (0.00 sec)

mysql>
[download]

We need the two columns for count so we have b,0,N and b,N,0 so the union does not obliterate one of the b's.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.