聚合表达式 - $dayOfWeek

函数构建

使用 aggregation 包提供的 DayOfWeek 函数构建 $dayOfWeek。

// bson.D{bson.E{Key:"weekday", Value:bson.D{bson.E{Key:"$dayOfWeek", Value:time.Now()}}}}
result := aggregation.DayOfWeek("weekday", time.Now())

方法构建（构建器）

使用 aggregation.NewBuilder() 的 DayOfWeekWithTimezone 方法构建 $dayOfWeek。

// bson.D{bson.E{Key:"weekday", Value:bson.D{bson.E{Key:"$dayOfWeek", Value:time.Now()}}}}
result := aggregation.NewBuilder().
    DayOfWeekWithTimezone("weekday", time.Now(), "Asia/Shanghai").
    Build()

无字段名构建

当表达式需要作为另一个表达式的参数时，可以使用 WithoutKey 变体构建不带输出字段名的表达式片段。

DayOfWeekWithoutKey

函数构建：

now := time.Now()

// bson.D{bson.E{Key:"$dayOfWeek", Value:now}}
expr := aggregation.DayOfWeekWithoutKey(now)

方法构建（构建器）：

now := time.Now()

// bson.D{bson.E{Key:"$dayOfWeek", Value:now}}
expr := aggregation.NewBuilder().
    DayOfWeekWithoutKey(now).
    Build()

DayOfWeekWithTimezoneWithoutKey

函数构建：

now := time.Now()

// bson.D{bson.E{Key:"$dayOfWeek", Value:bson.D{bson.E{Key:"date", Value:now}, bson.E{Key:"timezone", Value:"Asia/Shanghai"}}}}
expr := aggregation.DayOfWeekWithTimezoneWithoutKey(now, "Asia/Shanghai")

方法构建（构建器）：

now := time.Now()

// bson.D{bson.E{Key:"$dayOfWeek", Value:bson.D{bson.E{Key:"date", Value:now}, bson.E{Key:"timezone", Value:"Asia/Shanghai"}}}}
expr := aggregation.NewBuilder().
    DayOfWeekWithTimezoneWithoutKey(now, "Asia/Shanghai").
    Build()