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[英]How to evaluate if a variable is equal to user input without having several if statements
[英]How to query (SQL) a variable amount of user input without rewriting multiple SQL statements
我正在創建一個 web 應用程序(使用 Flask),其中用戶可以 select 和輸入變量,然后根據所選變量從數據集中生成 output。 這些可能的變量可以在下面的 HTML POST 表單中看到,並被饋送到后端以允許在其他代碼塊中看到 SQL 查詢。
我遇到的問題是,當用戶選擇一些輸入變量但將其他變量留空時,查詢會返回所有數據。
例如,如果從表單的下拉列表之一中選擇了值“金融犯罪”,但沒有填寫其他下拉列表/文本輸入,則查詢將返回所有可能的結果。 而我想要的結果是查詢返回 Category=Financial Crime 的所有行。
我知道我可以編寫一個if
語句來排除任何值為''
輸入變量,但這需要為每個可能的結果重新編寫查詢,我確信必須有一條路線以更簡單、更優化的方式執行此操作.
HTML:
<form method="POST">
<div class="row">
<div class="col">
<p>Enter Company/Product name:</p>
<input type="text" name="name" class="form-control">
</div>
<br><br>
<div class="col">
<p>Enter Keywords (delimited by comma):</p>
<input type="text" name="keywords" class="form-control">
</div>
</div>
<br>
<div class="row">
<div class="col-sm text-left">
<label for="category">Choose a category: </label>
<br>
<select name="category" id="category">
<option value="">Select Category</option>
<option value="Financial Crime">Financial Crime</option>
<option value="Regulatory Change">Regulatory Change</option>
</select>
</div>
<div class="col-sm text-center">
<label for="maturity">Choose maturity: </label>
<br>
<select name="maturity" id="maturity">
<option value="">Select Maturity</option>
<option value="Incumbent">Incumbent</option>
<option value="Challenger">Challenger</option>
<option value="New kid">New kid</option>
</select>
</div>
<div class="col-sm text-right">
<label for="under_tech">Choose underlying tech: </label>
<br>
<select name="under_tech" id="under_tech">
<option value="">Select Underlying Tech</option>
<option value="AI/ML">AI/ML</option>
<option value="Cloud">Cloud</option>
<option value="Blockchain">Blockchain</option>
</select>
</div>
</div>
<br><br>
<div class="row float-right">
<input class="btn btn-primary" type="submit" value="Search">
</div>
</form>
Python(燒瓶)/SQL:
@app.route('/advancedsearch', methods=['GET', 'POST'])
def advancedsearch():
if request.method == 'POST':
category = request.form.get('category')
maturity = request.form.get('maturity')
under_tech = request.form.get('under_tech')
keywords = request.form.get('keywords')
name = request.form.get('name')
attribs = [name,keywords,category,maturity,under_tech]
with db.connect() as conn:
# Query to find products with selected attributes
qry = """SELECT CompanyName,ProductName,Category,CompanyWebsite,Logo
FROM directory_data.full_dataset
WHERE Company_description LIKE %s
AND Underlying_Tech LIKE %s
AND Company_Maturity LIKE %s
AND Category LIKE %s
AND CompanyName LIKE %s OR ProductName LIKE %s"""
results = conn.execute(qry, ("%"+attribs[1]+"%","%"+attribs[4]+"%","%"+attribs[3]+"%","%"+attribs[2]+"%","%"+attribs[0]+"%","%"+attribs[0]+"%")).fetchall()
if results:
return render_template('advancedsearch.html', results=results, attribs=attribs)
else:
error = 'Results not found'
return render_template('advancedsearch.html', error=error, attribs=attribs)
return render_template('advancedsearch.html')
在您看來,將通配符%
指定為任何缺少或為空的變量的默認值:
category = request.form.get('category') or '%'
maturity = request.form.get('maturity') or '%'
etc.
此外,這變得不必要:
"%"+attribs[1]+"%"
您可以只使用attribs[1]
,因為LIKE
已經進行了 substring 匹配。 CompanyName LIKE apple
與CompanyName LIKE %apple%
完全相同。
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