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From:Hu Qinan Date:March 9 2003 3:52pm
Subject:alias a select query
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Dear all,

A table "book" looks like this:

"page"  "content"
--------------
1       abc
1       de
2       fgh
3       ijk
3       lmn
3       opq
...
210     z

I need a query to randomly select 90% of all pages and their
corresponding contents.

I have written the following querys. But I have problems to combine
them into a single one. (I use mysql.)

// Randomly select 40 pages of the book.
Query1: SELECT DISTINCT page FROM tbl ORDER BY RAND() LIMIT 40;

// Count the total pages of the book. But how to use this value in the
LIMIT clause in the above query to indicate 90% of all pages?
Query2: SELECT COUNT(DISTINCT page) FROM book;

// How to embed/alias Query1 in Query3?
Query3: SELECT * FROM book WHERE page IN Q1;

Thanks a lot.

Thread
alias a select queryHu Qinan9 Mar
  • Re: alias a select queryPaul DuBois9 Mar