Using Preloaded Data¶

This guide will show you how to use AST Builder to query data that has already been loaded into memory, as opposed to querying data from storage. This is similar to SQL's VALUES functionality.

Creating a Values Object¶

To create a values() object, you can either provide a vector of strings or a vector of vectors of strings. Each inner vector represents a row of data, and each string within the inner vector represents a value in that row.

use gluesql_core::ast_builder::values;

let actual = values(vec!["1, 'Glue'", "2, 'SQL'", "3, 'Rust'"])
    .execute(glue)
    .await;

let actual = values(vec![
    vec!["1", "'Glue'"],
    vec!["2", "'SQL'"],
    vec!["3", "'Rust'"],
])
.execute(glue)
.await;

Sorting Results (ORDER BY)¶

To sort the results of a values() query, use the order_by() method.

let actual = values(vec!["1, 'Glue'", "2, 'SQL'", "3, 'Rust'"])
    .order_by("column2 desc")
    .execute(glue)
    .await;

Pagination (OFFSET, LIMIT)¶

You can paginate the results of a values() query using the offset() and limit() methods.

let actual = values(vec!["1, 'Glue'", "2, 'SQL'", "3, 'Rust'"])
    .offset(1)
    .execute(glue)
    .await;

let actual = values(vec!["1, 'Glue'", "2, 'SQL'", "3, 'Rust'"])
    .limit(2)
    .execute(glue)
    .await;

Querying Preloaded Data¶

To query preloaded data using the values() object, you can call the select() method, and then use the project() method to specify the columns you want to include in the result.

let actual = values(vec!["1, 'Glue'", "2, 'SQL'", "3, 'Rust'"])
    .alias_as("Sub")
    .select()
    .project("column1 AS id")
    .project("column2 AS name")
    .execute(glue)
    .await;