SQL Query Builder

The builder pattern constructs a complex object step by step and produces the final result at the end, so callers can set the parts in any order.

Each part is a keyword, a space, and its text:

• select <columns>: comma-separated column names (spaces around commas may vary). Optional; the default is *.
• from <table>: required.
• where <condition>, order <columns>, limit <n>: optional.

If a keyword appears more than once, the last one wins. Build the query in this fixed order, with single spaces:

SELECT <columns> FROM <table>[ WHERE <condition>][ ORDER BY <columns>][ LIMIT <n>]

In the SELECT list, trim each column and join them with , . All other texts are copied unchanged.

Implement query_builder(parts).

Input

parts: The parts, in any order.

Output

Return the SQL query string.

सीमाएँ

1 ≤ number of parts ≤ 20

At least one from part; each part has at most 100 characters

उदाहरण

इनपुट:
parts = ["where age \u003e 18", "from users", "select name,age"]

अपेक्षित आउटपुट:
expected = "SELECT name, age FROM users WHERE age \u003e 18"

इनपुट:
std::vector<std::string> parts = {"where age \u003e 18", "from users", "select name,age"};

अपेक्षित आउटपुट:
std::string expected = "SELECT name, age FROM users WHERE age \u003e 18";

इनपुट:
string[] parts = new string[] {"where age \u003e 18", "from users", "select name,age"};

अपेक्षित आउटपुट:
string expected = "SELECT name, age FROM users WHERE age \u003e 18";

इनपुट:
parts = ["from orders", "limit 10", "order total DESC"]

अपेक्षित आउटपुट:
expected = "SELECT * FROM orders ORDER BY total DESC LIMIT 10"

इनपुट:
std::vector<std::string> parts = {"from orders", "limit 10", "order total DESC"};

अपेक्षित आउटपुट:
std::string expected = "SELECT * FROM orders ORDER BY total DESC LIMIT 10";

इनपुट:
string[] parts = new string[] {"from orders", "limit 10", "order total DESC"};

अपेक्षित आउटपुट:
string expected = "SELECT * FROM orders ORDER BY total DESC LIMIT 10";

संदर्भ

यह चुनौती CodeUtility के लिए अनुकूलित की गई है। ऊपर दिए गए स्टेटमेंट और सीमाओं का पालन करें।

• Refactoring.Guru, Design Patterns
• Gamma, Helm, Johnson, Vlissides, Design Patterns: Elements of Reusable Object-Oriented Software