Write SQL queries in a simple and composable way.

The main goal is to find the best balance between write idiomatic SQL queries and manage scenarios of complex query composition mixed with conditional clauses.

Quick Start

```rust use sqlquerybuilder as sql;

let mut select = sql::Select::new() .select("id, login") .from("users") .where_clause("login = $1");

let is_admin = true;

if isadmin { select = select.and("isadmin = true"); }

let query = select.as_string();

println!("{}", query); ```

Output

sql SELECT id, login FROM users WHERE login = $1 AND is_admin = true

Feature Flags

SQL Query Builder comes with the following optional features: - postgresql enable Postgres syntax

You can enable features like

```toml

Cargo.toml

sqlquerybuilder = { version = "1.x.x", features = ["postgresql"] } ```

How it's works

In simple terms this library will not try to understand what you are writing inside the arguments, this is good because it's removes a lot of complexity and verbosity to generate a SQL query, in contrast debugging tends to be more difficult and silly error can araise. The lib has the debug() method with a nice output to minimize the effort to debug a complex query.

Consecutive calls to the same clause will accumulates values respecting the order of the calls, the two select produce the same SQL query

```rust use sqlquerybuilder as sql;

let select = sql::Select::new() .select("id, login");

let select = sql::Select::new() .select("id") .select("login"); ```

Methods like limit and offset will override the previous value, the two select is equivalent

```text use sqlquerybuilder as sql;

let select = sql::Select::new() .limit("1000") .limit("123");

let select = sql::Select::new() .limit("123"); ```

The library ignores the order between clauses so the two selects are the same

```rust use sqlquerybuilder as sql;

let select = sql::Select::new() .select("id, login") .from("users") .where_clause("login = $1");

let select = sql::Select::new() .from("users") .where_clause("login = $1") .select("id, login"); ```

You can conditionally add a clause mutating the select

```rust use sqlquerybuilder as sql;

let mut select = sql::Select::new() .select("id, login") .from("users") .where_clause("login = $1");

let shouldIncludesAddress = true;

if shouldIncludesAddress { select = select.innerjoin("address on user.login = address.ownerlogin"); } ```

Composition

Composition is very welcome to write complex queries, this feature makes the library shine

```rust use sqlquerybuilder as sql;

fn project(select: sql::Select) -> sql::Select { select .select("u.id, u.name as username, u.login") .select("a.name as addressname") .select("o.name as product_name") }

fn relations(select: sql::Select) -> sql::Select { select .from("users u") .innerjoin("address a ON a.userlogin = u.login") .innerjoin("orders o ON o.userlogin = u.login") }

fn conditions(select: sql::Select) -> sql::Select { select .where_clause("u.login = $1") .and("o.id = $2") }

fn asstring(select: sql::Select) -> String { select.asstring() }

let query = Some(sql::Select::new()) .map(project) .map(relations) .map(conditions) .map(as_string) .unwrap();

println!("{}", query); ```

Output (indented for redability)

sql SELECT u.id, u.name as user_name, u.login, a.name as address_name, o.name as product_name FROM users u INNER JOIN address a ON a.user_login = u.login INNER JOIN orders o ON o.user_login = u.login WHERE u.login = $1 AND o.id = $2

Raw queries

You can use the raw method to accomplish some edge cases that are hard to rewrite into the Select syntax. The select.raw() method will put any SQL you define on top of the output

```rust use sqlquerybuilder as sql;

let rawquery = "\ select u.id as userid, addr.* \ from users u \ inner join address addr on u.login = addr.ownerlogin\ "; let select = sql::Select::new() .raw(rawquery) .where_clause("login = $1"); ```

To a more precisely use case your can use the select.raw_before() and select.raw_after()

```rust use sqlquerybuilder as sql;

let rawquery = "\ from users u \ inner join address addr on u.login = addr.ownerlogin\ "; let select = sql::Select::new() .select("u.id as userid, addr.*") .rawbefore(sql::SelectClause::Where, rawquery) .whereclause("login = $1"); ```

```rust use sqlquerybuilder as sql;

let rawquery = "\ from users u \ inner join address addr on u.login = addr.ownerlogin\ "; let select = sql::Select::new() .select("u.id as userid, addr.*") .rawafter(sql::SelectClause::Select, rawquery) .whereclause("login = $1"); ```

Debugging queries

Sometimes it's more ease just print de current state of the query builder, to do this just add the .debug() method at any part of the builder, note that the where clause will not be printed because the debug was added before

```rust use sqlquerybuilder as sql;

let mut select = sql::Select::new() .select("id, login") .from("users") .debug() .where_clause("login = $1"); ```

Output

sql SELECT id, login FROM users

See the documentation for more builders like Insert, Update and Delete