How to filter data from database table? - node.js

Question

How can I do the filtration inside database table, and get the data base on my conditions or filters.
Table: customers:
Lets assume a situation. I have a table name customers,
Now I am having columns for store customer address (customer address is type of object {}) address column is typeOf object with porperties country, state, city, etc. another column I am having for dob (date of birth),
Now I want to take certain inputs or filters from user, all the filters can be optional,
for example let's assume there are 3 filters country, fromDob, toDob, and state, now we may or may not have fromDOB or toDOB parameter if user want to fetch the data between the specific date of birth or example between 2009-12-12 to 2011-12-12. but there are some more filters as well for example with dob filters there is a filter for country and the country should be US so I need to fetch that data from customer_account table where dob is between 2009-12-12 and 2011-12-12 and the country should be US inside address object.
but there is one more filter name state, but somtime user may paas all the filters or sometime user just want to fetch the data for some specific filters. all the filters are optional. user can use any of them or few of them or all of them it's user's wish, what my task is, to fetching the data based on user's provided filters.
But I am not sure how can I do so.
I am implementing all the code inside nodejs and Knexjs.
Any help?
Thanks

Answer 1

you can use if condition inside the where conditions builder
knex('users')
.where((builder) => {
if(fromDob)
builder
.Where('Dob', '>', fromDob)
if(state)
builder.where('state', state)
return builder
}
)

Answer 2

Ok, for you to be able to filter the data between date of birth you need to use this approach in mongoDB
$filter: {
input: <array>,
cond: <expression>,
as: <string>,
limit: <number expression>
}
$input field is the array of documents that resolves to an array
$cond An expression that resolves to a boolean value used to determine if an element should be included in the output array. The expression references each element of the input array
$as Optional. A name for the variable that represents each individual element of the input array. If no name is specified, the variable name defaults to this.
$limit Optional. A number expression that restricts the number of matching array elements that
$filter
returns. You cannot specify a limit less than 1. The matching array elements are returned in the order they appear in the input array.
Example
db.customers.aggregate({
$filter: {
input: [userInput],
as: "date"
cond: [
{
"date": {
$lt: "2011-12-12" $and $gt: "2009-12-12"
}
}, {
"address": {
$eq: "US"
}
}
]
}
});
Result
| id | dob | Address |
|:---- |:------:| -----:|
| 1 | "date" | {country: "US", state: "", address: ""} |
I hope this helps.