Struct sea_query::query::CaseStatement

source ·

pub struct CaseStatement { /* private fields */ }

Implementations§

source §

impl CaseStatement

source

pub fn new() -> Self

Creates a new case statement expression

§Examples

use sea_query::{*, tests_cfg::*};

let query = Query::select()
    .expr_as(
        CaseStatement::new()
            .case(Expr::col((Glyph::Table, Glyph::Aspect)).is_in([2, 4]), true)
            .finally(false),
         Alias::new("is_even")
    )
    .from(Glyph::Table)
    .to_owned();

assert_eq!(
    query.to_string(PostgresQueryBuilder),
    r#"SELECT (CASE WHEN ("glyph"."aspect" IN (2, 4)) THEN TRUE ELSE FALSE END) AS "is_even" FROM "glyph""#
);

source

pub fn case<C, T>(self, cond: C, then: T) -> Self
where C: IntoCondition, T: Into<SimpleExpr>,

Adds new CASE WHEN to existing case statement.

§Examples

use sea_query::{*, tests_cfg::*};

let query = Query::select()
    .expr_as(
            Expr::case(
                Expr::col((Glyph::Table, Glyph::Aspect)).gt(0),
                "positive"
             )
            .case(
                Expr::col((Glyph::Table, Glyph::Aspect)).lt(0),
                "negative"
             )
            .finally("zero"),
         Alias::new("polarity")
    )
    .from(Glyph::Table)
    .to_owned();

assert_eq!(
    query.to_string(PostgresQueryBuilder),
    r#"SELECT (CASE WHEN ("glyph"."aspect" > 0) THEN 'positive' WHEN ("glyph"."aspect" < 0) THEN 'negative' ELSE 'zero' END) AS "polarity" FROM "glyph""#
);

source

pub fn finally<E>(self, else: E) -> Self
where E: Into<SimpleExpr>,

Ends the case statement with the final ELSE result.

§Examples

use sea_query::{*, tests_cfg::*};

let query = Query::select()
    .expr_as(
        Expr::case(
            Cond::any()
                .add(Expr::col((Character::Table, Character::FontSize)).gt(48))
                .add(Expr::col((Character::Table, Character::SizeW)).gt(500)),
            "large"
        )
        .case(
            Cond::any()
                .add(Expr::col((Character::Table, Character::FontSize)).between(24,48))
                .add(Expr::col((Character::Table, Character::SizeW)).between(300,500)),
            "medium"
        )
        .finally("small"),
        Alias::new("char_size"))
    .from(Character::Table)
    .to_owned();

assert_eq!(
    query.to_string(PostgresQueryBuilder),
    [
        r#"SELECT"#,
        r#"(CASE WHEN ("character"."font_size" > 48 OR "character"."size_w" > 500) THEN 'large'"#,
        r#"WHEN (("character"."font_size" BETWEEN 24 AND 48) OR ("character"."size_w" BETWEEN 300 AND 500)) THEN 'medium'"#,
        r#"ELSE 'small' END) AS "char_size""#,
        r#"FROM "character""#
    ]
    .join(" ")
);