Function json_build_array_2 

pub fn json_build_array_2<V1: SingleValue, V2: SingleValue, value_1, value_2>(
    value_1: value_1,
    value_2: value_2,
) -> json_build_array_2<V1, V2, value_1, value_2>
where
    value_1: AsExpression<V1>,
    value_2: AsExpression<V2>,

Available on crate feature postgres_backend only.

Builds a possibly-heterogeneously-typed JSON array out of a variadic argument list. Each argument is converted as per to_json.

Example

let result = diesel::select(json_build_array_0()).get_result::<serde_json::Value>(connection)?;
assert_eq!(json!([]), result);

let result = diesel::select(json_build_array_1::<Text, _>("abc"))
    .get_result::<serde_json::Value>(connection)?;
assert_eq!(json!(["abc"]), result);

let result = diesel::select(json_build_array_2::<Text, Double, _, _>("abc", 3.1415))
    .get_result::<serde_json::Value>(connection)?;
assert_eq!(json!(["abc", 3.1415]), result);

let result = diesel::select(json_build_array_1::<Record<(Text, Double)>, _>(sql::<Record<(Text, Double)>>("ROW('abc',3.1415)")))
    .get_result::<serde_json::Value>(connection)?;
assert_eq!(json!([
    {
        "f1":"abc",
        "f2":3.1415
    }
 ]), result);

let result = diesel::select(json_build_array_1::<Array<Integer>, _>(vec![1, 2, 3]))
    .get_result::<serde_json::Value>(connection)?;
assert_eq!(json!([ [1, 2, 3] ]), result);

let result = diesel::select(json_build_array_2::<Nullable<Text>, Double, _, _>(None::<String>, 3.1415))
    .get_result::<serde_json::Value>(connection)?;
assert_eq!(json!([None::<String>, 3.1415]), result);

let result = diesel::select(json_build_array_1::<Record<(Nullable<Text>, Double)>, _>(sql::<Record<(Nullable<Text>, Double)>>("ROW(null,3.1415)")))
    .get_result::<serde_json::Value>(connection)?;

assert_eq!(json!([
    {
        "f1":None::<String>,
        "f2":3.1415
    }
 ]), result);

Variadic functions

This function is variadic in SQL, so there’s a family of functions on a diesel side:

json_build_array_0, json_build_array_1, … json_build_array_n

Here, the postfix number indicates repetitions of variadic arguments. To use this function, the appropriate version with the correct argument count must be selected.

Controlling the generation of variadic function variants

By default, only variants with 0, 1, and 2 repetitions of variadic arguments are generated. To generate more variants, set the DIESEL_VARIADIC_FUNCTION_ARGS environment variable to the desired number of variants.

For a greater convenience this environment variable can also be set in a .cargo/config.toml file as described in the cargo documentation.