SELECT s.Treal, s.Ttheory, sEx.`code`, s.add_predata, sEx.displacementData, sEx.forceData, sEx.experimentName, sLa.LaName, sLa.LaData, sYa.YaData, sYa.YaName, CASE WHEN sBen.`Name` IS NOT NULL THEN sBen.Ri END AS Ri, CASE WHEN sBen.`Name` IS NOT NULL THEN sBen.Ro END AS Ro, CASE WHEN sBen.`Name` IS NOT NULL THEN sBen.heighBottom END AS heighBottom, CASE WHEN sBen.`Name` IS NOT NULL THEN sBen.heighTop END AS heighTop, CASE WHEN sMea.CName IS NOT NULL THEN sMea.Chigh END AS Chigh, CASE WHEN sMea.CName IS NOT NULL THEN sMea.Clow END AS Clow, CASE WHEN sMea.CName IS NOT NULL THEN sMea.CName END AS CName FROM addendumtable s JOIN experimenttable sEx ON sEx.`code` = s.Exobject JOIN featurelatable sLa ON sLa.LaName = s.featuretable_id_la JOIN featureyatable sYa ON sYa.YaName = s.featuretable_id_ya LEFT JOIN benchmarktable sBen ON sBen.`Name` = s.benchmark_id OR sBen.`Name` IS NULL LEFT JOIN measurementtable sMea ON sMea.CName = s.measure_id OR sMea.CName IS NULL WHERE s.Exobject = 'YSH-111';
时间: 2024-02-14 18:24:29 浏览: 20
这是一个比较复杂的SQL查询语句,它包含多个表的连接和数据的筛选。该查询的目的可能是从多个表中获取与指定实验代码('YSH-111')相关的数据。
具体来说,该查询将addendumtable、experimenttable、featureatable、featureyatable、benchmarktable、measurementtable这些表连接起来,并选择一些列来返回。其中,JOIN操作用于连接多个表,LEFT JOIN操作用于在一个表中找不到与另一个表中匹配的行时,仍然返回左表中的所有行。而WHERE子句用于筛选出符合条件的数据。
需要注意的是,该查询中的列名可能比较特殊,可能需要根据实际表结构进行调整。另外,该查询中的CASE WHEN ... THEN ... END语句用于根据不同的条件返回不同的值,也是一种比较常见的SQL技巧。
相关问题
c语言实现4096个点的FFT程序
由于FFT算法比较复杂,实现4096点的FFT需要一定的数学和编程知识。以下是一个简单的C语言实现4096点FFT的程序:
```c
#include <stdio.h>
#include <math.h>
#define N 4096
void fft(double *real, double *imag, int n, int inverse) {
int i, j, k, m;
double tempreal, tempimag, wreal, wimag, treal, timag;
double pi = inverse ? -acos(-1.0) : acos(-1.0);
for (i = 0; i < n; i++) {
j = 0;
for (k = 0; k < log2(n); k++) {
j |= ((i >> k) & 1) << (log2(n) - 1 - k);
}
if (j > i) {
tempreal = real[i];
real[i] = real[j];
real[j] = tempreal;
tempimag = imag[i];
imag[i] = imag[j];
imag[j] = tempimag;
}
}
for (m = 2; m <= n; m <<= 1) {
wreal = cos(2.0 * pi / m);
wimag = sin(2.0 * pi / m);
for (k = 0; k < n; k += m) {
treal = 1.0;
timag = 0.0;
for (i = k; i < k + (m >> 1); i++) {
tempreal = treal * real[i + (m >> 1)] - timag * imag[i + (m >> 1)];
tempimag = treal * imag[i + (m >> 1)] + timag * real[i + (m >> 1)];
real[i + (m >> 1)] = real[i] - tempreal;
imag[i + (m >> 1)] = imag[i] - tempimag;
real[i] += tempreal;
imag[i] += tempimag;
tempreal = treal * wreal - timag * wimag;
timag = treal * wimag + timag * wreal;
treal = tempreal;
}
}
}
if (inverse) {
for (i = 0; i < n; i++) {
real[i] /= n;
imag[i] /= n;
}
}
}
int main() {
double real[N], imag[N];
int i;
// 生成输入信号
for (i = 0; i < N; i++) {
real[i] = sin(2.0 * acos(-1.0) * i / N);
imag[i] = 0.0;
}
// 进行FFT变换
fft(real, imag, N, 0);
// 输出结果
for (i = 0; i < N; i++) {
printf("%f + %fi\n", real[i], imag[i]);
}
return 0;
}
```
该程序通过调用fft函数实现了对4096个点进行FFT变换,其中real和imag分别为输入实数和虚数数组,n为变换点数,inverse为0表示正变换,为1表示逆变换。程序中使用了蝴蝶运算和位逆序置换两种常用的实现FFT的方法。最后,程序输出了变换后的实部和虚部。