The CASE WHEN statement in MySQL is a conditional statement that allows you to check for specific conditions and then perform actions based on those conditions. It can be used as an alternative to the IF/ELSEIF statements in MySQL.
The basic syntax of the CASE WHEN statement is as follows:
SELECT column1, column2,
CASE
WHEN condition1 THEN result1
WHEN condition2 THEN result2
WHEN condition3 THEN result3
ELSE default_result
END
FROM table_name;
In this example, the CASE statement checks for three different conditions, and if any of them are true, it returns the corresponding result. If none of the conditions are true, it returns the default_result.
Here’s a more detailed breakdown of how the CASE WHEN statement works:
- Start with the SELECT statement, which specifies the columns to return.
- Use the CASE keyword to begin the conditional statement.
- Follow the CASE keyword with one or more WHEN statements, which specify the conditions to check.
- After each WHEN statement, specify the result to return if the condition is true.
- If there are multiple WHEN statements, they will be evaluated in order until one of them is true.
- After all the WHEN statements, include an ELSE statement to specify the default result to return if none of the conditions are true.
- Finally, end the CASE statement with the END keyword.
Overall, the CASE WHEN statement provides a flexible way to handle conditional logic in MySQL queries.
![/data # iw --debug dev wlan0 connect -w "lucky-5g" auth open key 0:1234567890
Usage: iw [options] dev connect [-w] [] [] [auth open|shared] [key 0:abcde d:1:6162636465] [mfp:req/opt/no]
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![驱动代码
void kalRxTaskletSchedule(struct GLUE_INFO *pr)
{
static unsigned int num = 0;
tasklet_hi_schedule(&pr->rRxTask[(num++)%NR_CPUS]);
// tasklet_hi_schedule(&pr->rRxTask);
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