for each output of a select statement, execute another query

Please consider this question:

A sqlite db with two tables, and I need to take bookName from one table and generate count on each of the results in another table.

$ sqlite3 Sqlite.db "select bookName from books" 
myBook.1
myBook.2
myBook.3
myBook.4
myBook.5

Tried subQuery, probably wrongly, with wrong results:

sqlite> select count(*) from tags where bookName = (select bookName from books);
753

This is what I am trying to do:

$ sqlite3 SSqlite.db "select bookName from books" | while read a ; do  sqlite3 Sqlite.db "select bookName,count(*) from tags where bookName = \"$a\""; done
myBook.1|753
myBook.2|677
myBook.3|573
myBook.4|656
myBook.5|103

This must be possible much simpler within SQL, any input is much appreciated!

>Solution :

If you want results only for the books in the table tags, then you should group by bookName:

SELECT COUNT(*) counter
FROM tags 
GROUP BY bookName;

If you want results for all the books in the table books then use a LEFT join and aggregation:

SELECT b.bookName, COUNT(t.bookName) counter
FROM books b LEFT JOIN tags t
ON t.bookName = b.bookName 
GROUP BY b.bookName;