The hard process of using the Rand function of the T-SQL to generate a random number

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> in the previous article minor-latin; mso-fareast-font-family:; mso-fareast-theme-font: minor-fareast;
Mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> the speed of inserting large amounts of data is improved; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family:
; Mso-fareast-theme-font: minor-fareast; mso-hansi-font-family: Calibri;
In mso-hansi-theme-font: minor-latin ">, a column of data uses Rankmso-fareast-font-family:; mso-fareast-theme-font: minor-fareast; mso-hansi-font-family:
Calibri; mso-hansi-theme-font: minor-latin "> functions are produced to counterfeit data.

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> the problem is, what if I want to update the value of this column? Maybe you can delete all of them. Just insert them again. But it's too slow. So I wrote the following code.

 

Color: blue; mso-font-kerning: 0pt; mso-no-proof: yes '> Update0pt; mso-no-proof: yes '> aTable Set aColumn = @ MaxInt * RAND ()

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> the results are totally unexpected, the values in this column are all the same!

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> okay, you can give it to Rand () mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> a seed. Just put IDmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> the column value is passed to Randmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> function.

 

Color: blue; mso-font-kerning: 0pt; mso-no-proof: yes '> Update0pt; mso-no-proof: yes '> aTable Set aColumn = @ MaxInt * RAND (ID)

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> result: IDmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> similar Randmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> values are also very close, as shown below.

 

1 1532427136

2 1532467150

3 1532507164

4 1532547178

5 1532587192

6 1532627206

7 1532667220

8 1532707234

9 1532747248

10 1532787262

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> NO, RANDmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> the function can be so linear. ~~~~~~~~ Calibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> basically, IDmso-ascii-theme-font can be calculated: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin ">=11mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin ">, Rankmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> function value. Fortunately, the results of each run are different.

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> give Randmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> the function transmits a non-linear value. The first thought is to use an exclusive or operation. What is the exclusive or? The first thought is time.

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> the following code is available.

 

Color: blue; mso-font-kerning: 0pt; mso-no-proof: yes '> Update0pt; mso-no-proof: yes'> aTable Set aColumn = Convert (int, RAND (datediff (MS, '2017-08-28 23:13:00 ', GETDATE () ^ ID) * @ MaxInt)

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> below is the running result.

 

1 1194104621

2 1194224663

3 1194184649

4 1194304691

5 1194264677

6 1194384719

7 1194344705

8 1194464748

9 1194424733

10 1194544776

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> fortunately, it's not linear, however, this value is still wandering in a small range.

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> I wanted to put Seedmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> a bit messy, if Randmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> function, make a messy Seedmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> and Randmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> what are functions? Isn't the output that converts a linear input into a non-linear output Seedmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> does the function work?

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> however, the last step is to save the country. Basic Assumptions: aColumnCalibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> the column is sufficient for Randommso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin ">. So update this column.

 

Color: blue; mso-font-kerning: 0pt; mso-no-proof: yes '> Update0pt; mso-no-proof: yes '> aTable Set aColumn = @ MaxInt * RAND (aColumn)

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> you can also choose Insertmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> Randmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> aColumnCalibri; mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin ">.

 

Mso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> is there any way to skip Randmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> transmits a random Seedmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> This allows Randmso-ascii-theme-font: minor-latin; mso-fareast-font-family:; mso-fareast-theme-font:
Minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin "> must a random number be returned?