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<pre><code>import sqlite3
conn = sqlite3.connect('food.db')
c = conn.cursor()
c.execute('''CREATE TABLE IF NOT EXISTS nutritional_values
(item, calories, total fat, protein)''')
items = [ ('Broccoli Chinese', 22, 0.7, 1.1),
('chia seeds', 490, 30.8, 15.6),
('blueberries', 57, 0.3, 0.7),]
c.executemany('INSERT INTO nutritional_values VALUES (?,?,?,?)',items)
c.execute('''CREATE TABLE IF NOT EXISTS food_consumption
(date, item, amount)''')
c.execute('DELETE FROM food_consumption')
consumed = [ ('24/8/2019', 'Broccoli Chinese', 1.5),
('24/8/2019', 'chia seeds', 0.35),
('24/8/2019', 'blueberries', 0.4),]
c.executemany('INSERT INTO food_consumption VALUES (?,?,?)',consumed)
conn.commit()
conn.close()
</code></pre>
<p>如果我跑:</p>
<pre><code>for row in c.execute('SELECT * FROM food_consumption'):
print(row[1])
</code></pre>
<p>如我所料,我得到:</p>
<pre><code>Broccoli Chinese
chia seeds
blueberries
</code></pre>
<p>但如果我跑了:</p>
<pre><code>for row in c.execute('SELECT * FROM food_consumption'):
print(row[1])
for number in c.execute('SELECT calories FROM nutritional_values WHERE item=(?)', (row[1],)):
print(number)
</code></pre>
<p>我得到:</p>
<pre><code>Broccoli Chinese
(22,)
</code></pre>
<p>所以它不再在表<code>'food_consumption'</code>中的所有行上循环,如何让它在所有行上循环</p>