select/save part of database into another database

I have database A of four columns: a, b, c, d, and want to save those rows of d values of less than -10 into another database B. How can I do it?

[Mohammad Sami]

Did you mean a Matlab table or matrix or an SQL Database ?

[addy fang]

It is an Excel table, can be read in to a Matlab matrix. For example, the first column is the name, second is address, third is height, and forth column is weight loss. I need to retable those with certain weight loss, less then -10 lbs.

Answer 1

[Mohammad Sami]

I assume you are able to read the excel directly using the readtable function.

% excelfilepath = 'C:\...';
% DBA = readtable(excelfilepath);
DBB = DBA(DBA.d < -10,:);
% exceloutpath = 'C:\....';
% writetable(DBB,exceloutpath);

[addy fang]

I tried, it gave some error:

z1=y(y.2<-10, :);

↑

Error: Invalid expression. Check for missing multiplication operator, missing or unbalanced

delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses.

[Mohammad Sami]

"2" in y.2 is not a valid vairable or column name. If y is a table see what is the column name.

If y is a matrix, use

z1=y(y(:,2)<-10, :);

[addy fang]

Great. Thank you.