Mysql 计算每个用户在第二个表中有多少条记录

I have 2 Tables (The relevant ones for this question). One for Customers, second for loans.
What I am trying to accomplish is to get each customer's information, and in addition to that how many loans he toked.

我的用户表

+--------+-------+-------+-----+
| cst_id | fname | lname | age |
+--------+-------+-------+-----+
|      1 | xx    | yy    |  11 |
|      2 | xx    | yy    |  22 |
|      3 | xx    | yy    |  33 |
|      4 | xx    | yy    |  44 |
|      5 | xx    | yy    |  55 |
+--------+-------+-------+-----+

贷款表

+---------+-----------------+
| cust_id | loan_variant_id |
+---------+-----------------+
|       1 |               1 |
|       1 |               2 |
|       2 |               3 |
|       2 |               1 |
|       3 |               1 |
+---------+-----------------+

We see that customers with ID 1 have 2 registered loans.

最后一张桌子应该是什么样子

您可以忽略新列"name"，因为它与问题无关.

+--------+-------+-------+-----+-------+------------+
| cst_id | fname | lname | age | name  | loan_count |
+--------+-------+-------+-----+-------+------------+
|      1 | xx    | yy    |  11 | xx yy |          2 |
|      2 | xx    | yy    |  22 | xx yy |          2 |
|      3 | xx    | yy    |  33 | xx yy |          1 |
|      4 | xx    | yy    |  44 | xx yy |          0 |
|      5 | xx    | yy    |  55 | xx yy |          0 |
+--------+-------+-------+-----+-------+------------+

我的SQL代码

SELECT
    *,
    CONCAT(fname, ' ', lname) AS name,
    COUNT(##some magic code please, at least what i think##) AS loan_count
FROM
    t_cst

现在我知道，通过这个查询，我可以在t_loans表中完成我想要的(计算每个用户 token 的贷款数量).然而，我对如何同时使用这两个查询有点困惑.

SELECT
    COUNT(cust_id) AS loansCountForEachCst
FROM
    t_loans
GROUP BY
    (cust_id)

有什么 idea 吗？