MySQL a field inserts the random number (inserts the random number to the MySQL database) _mysql

Common code

Update ' table name ' Set click=click*0.01 where classid= ' 2 ' and click>2000

We often encounter random problems, and here's a way to solve random numbers.

When constructing test data, we need to insert random data into the test table. The method for constructing test data is as follows, with update as an example

Step 1: The SQL function for the random number is rand (), and Rand () produces a decimal between 0-1.

Step 2: *10 rand ()

A decimal number between 1-10 is generated and can be converted using Ceil.

Step 3: Use cast to do type conversion

The use of cast is as follows:

Cast (value as type)

Binary, with the effect of BINARY prefix: BINARY

Character type, with parameters: CHAR ()

Dates: Date

Time: Times

Date-time: DATETIME

Floating point numbers: DECIMAL

Integer: Signed

unsigned integer: UNSIGNED

SELECT CAST (rand () *10 as signed) as Rand

Step 4: Run the SQL statement

UPDATE Storm_effect_info S SET

S.FHTP = (SELECT CAST (rand () *10 as signed) as RAND) WHERE s.id = 13