Question

我想要一个MySQL查询来获取上一年的记录。我已经写了一个查询来获取当前年份的记录，但我也想要上一年的记录。有一个名为＆＃34; date_created＆＃34;根据这个日期，我必须获取材料的状态。

SELECT material_status, COUNT(*) c
FROM purchase_order
WHERE YEAR(date_created) = YEAR(CURDATE()) AND material_status='open';

Answer 1

获取去年的数据

open System
open System.IO
open FSharp.Core.Operators
open MathNet.Numerics
open MathNet.Numerics.LinearAlgebra
open MathNet.Numerics.LinearAlgebra.Double
open MathNet.Numerics.Distributions
open DiffSharp.Numerical.Float64
open NLoptNet

let (.*) (m1 : Matrix<float>) (m2 : Matrix<float>) =
    m1.Multiply(m2)

let (.+) (m1 : Matrix<float>) (m2 : Matrix<float>) =
    m1.Add(m2)

let (.-) (m1 : Matrix<float>) (m2 : Matrix<float>) =
    m1.Subtract(m2)


let V = matrix [[1.;      0.5;    0.2]
                [0.5;      1.;    0.]
                [0.2;      0.;    1.]]
let dat = (DenseMatrix.init 200 3 ( fun i j -> Normal.Sample(0., 1.) )) .* V.Cholesky().Factor
let y = DenseMatrix.init 200 1 (fun i j -> 0.)
let x0 = DenseMatrix.init 200 1 (fun i j -> 0.)
let x1 = DenseMatrix.init 200 1 (fun i j -> 0.)
for i in 0 .. 199 do
    y.[i, 0] <- dat.[i, 0]
    x0.[i, 0] <- dat.[i, 1]
    x1.[i, 0] <- dat.[i, 2]

let ll (th : float array) =
    let t1 = x0.Multiply(th.[0]) .+ x1.Multiply(th.[1])
    let res = (y .- t1).PointwisePower(2.)
    res.ColumnAbsoluteSums().Sum() / 200.

let oFunc (th : float array) (gradvec : float array) =
    match gradvec with
    | null  -> ()
    | _     -> (grad ll th).CopyTo(gradvec, 0)

    ll th

let cFunc (th : float array) (gradvec : float array) =
    match gradvec with
    | null  -> ()
    | _     -> (grad ll th).CopyTo(gradvec, 0)

    th.[0] + th.[1]

let fitFunc () =
    let solver = new NLoptSolver(NLoptAlgorithm.LN_COBYLA, uint32(2), 1e-7, 100000)
    solver.SetLowerBounds([|-10.; -10.;|])
    solver.SetUpperBounds([|10.; 10.;|])
    //solver.AddEqualZeroConstraint(cFunc)
    solver.SetMinObjective(oFunc)
    let initialValues = [|1.; 2.;|]
    let objReached, finalScore = solver.Optimize(initialValues)
    objReached |> printfn "%A"
    let fittedParams = initialValues
    fittedParams |> printfn "%A"
    fittedParams

let fittedParams = fitFunc() |> DenseVector
let yh = DenseMatrix.init 200 1 (fun i j -> 0.)
for i in 0 .. 199 do
    yh.[i, 0] <- dat.[i, 1] * fittedParams.[0] + dat.[i, 2] * fittedParams.[1]


Chart.Combine([Chart.Line(y.Column(0), Name="y")
               Chart.Line(yh.Column(0), Name="yh")
               |> Chart.WithLegend(Title="Model", Enabled=true)] )
               |> Chart.Show

Answer 2

查询 MySQL 的日期时间函数是如何工作的

试试这个：

select 
CURRENT_USER() user, 
CURRENT_TIME() current_time, 
CURRENT_DATE() current_date, 
year(CURRENT_DATE()) current_year, 
YEAR(DATE_SUB(CURDATE(), INTERVAL 1 YEAR)) previous_year;

MySQL获得上一年的记录

2 个答案: