mysql - Is it possible to SELECT either 1 or 2 columns? -

-

I am thinking that within MySQL (without PHP), you can make a condition that if true SELECT 1,2 but if false then select 1? Or something similar to MySQL syntax, which can accomplish the same effect?

Thank you.

There is no way to select at least one fixed number column of a stored procedure. The number of columns obtained from the selection statement of any one is constant. The best thing you can do is two case statements, one that will return the null in some circumstances, there are still two columns, but depending on your condition one will be extremely essential.

Comments

Post a Comment

Popular posts from this blog

php - PDO bindParam() fatal error -

-
I am trying to learn PDO, now I have written this small code, but it gives me a serious error: Fatal error: Call a member function at a non-object dot () ... $ con = new mysqli ("127.0.0.1", "root", "", "csvdangercheck"); $ Query = $ con- & gt; ("Id,` var1`, `var2`) values ​​(" id,: var1,: var2) ";); $ query- & gt; bypass pattern (': id', $ id); $ query- & gt; BindParam (': var1', $ VAL1); $ Query- & gt; bindParam (': var2', $ val2); $ Query-> Executed (); I Trying to use print_r ($ con-> errorInfo ()) but Fatal error: Undefined method mysqli :: errorInfo ( ) ... can someone tell me what am I missing? Flaffeh said, you have PDO Missing Mysqy, try it: $ con = new PDO ('mysql: host = 127.0.0.1; dbname = csvdangercheck', 'root', '');
Read more

php - How can I cram 6+31 numeric characters into 22 alphanumeric characters? -

-
I have a 6 digit number and a 31-digit number (such as "234536" and "201103231043330478311223582826") that I The API needs to be crawled in the same 22-character alphanumeric field that uses PHP. I tried to convert each one to 32 (using custom code could not handle the base_convert () large number) and to connect with a single-character delimiter, but It only gives me 26 characters This is a restore API, so the letters should be URI-protected. I would like to do a database table cross with two references without reference to another reference value, if possible, any suggestions? Instead use a radix of 62. This will give you 22 characters for the top, 3.35 for the pre and 17.3 for the next. & gt; & Gt; & Gt; Math.log (10 ** 6) /math.log (62) 3.3474826039165504 & gt; & Gt; & Gt; Math.log (10 ** 31) /math.log (62) 17.295326786902177
Read more

mysql - where clause in inner join query -

-
Please help me about this question: Look for functions ($ userpno) } {Echo $ userpno; $ This-> query = "SELECT task.employee_id, task.user_id, task.service_id, service.name AS servicename, service.description AS servicedescription, employee.name as employineame, employee.pic_path employment, employee.pic_path from work Work.user_id = '$ userpno' Join the INNER employee. Pno = task.employee_id Join INNER user user.pno = task.user_id service.service_id = task.service_id "INNER service; } query works perfectly without: WHERE task.user_id = '$ userpno' my Also try this method: WHERE task.user_id = $ userpno but it does not work. Error: Warning: mysqli_fetch_array () parameter 1 is expected to be mysqli_result, given in Boolean C: \ wamp \ www \ admin \ classes \ Task Php on line 22 Please tell me where I say where is it. Try: $ this-> query = "SELECT Task.employee_id, task.user_id, task.service_id, service.name AS s...
Read more