How to run large SQL statements on new lines

Good afternoon all...

Little questions regarding SQL statements in Matlab. I am currently using 2018 version and have produced a script that connects to a database and extracts data using a simple SQL statement.

I am trying to understand how you can tidy up the script by using larger SQL queries to extract more data by using a new line e.g ...

if true
  % %Open the connection string- connect to Database
conn.Open(connection_string1);
SQL = 'select table.leg_no', ...
     'from table');
end

This will only work if I place the whole statement on one line. I have tried [] and ().

Eventually I would like to create larger SQL queries that can be stored into variables to use in a GUI.

Really appreciate some help with this..Many thanks :-)

Please note: I am not running with the DataBase Toolbox.

Answer 1

[Guillaume]

Your question is really about how to input a char vector using more than one line:

SQL = ['select table.leg_no ', ...
       'from table ', ...
       'where table.col1 = 12345'];

See also this

edit: don't forget the spaces as I did originally, matlab won't insert them between each line for you.

Answer 2

[Dan Howard]

Many thanks for clearing that up for me. The only problem I seem to be having is that..

1.

if true
  % SQL = [['select table.leg_no ', ...
     'from table '];
end

This executes the SQl query ok

2.

if true
  % SQL = ['select table.leg_no ', ...
     'from table ', ...
     'where table.col1 = 12345'];
end

This throws an Error which is...

Source: Microsoft OLE DB Provider for SQL Server Description: Invalid column name '12345'.

Error in Database (line 29) myrecordset=conn.Execute(SQL); % execute sql statement

Little confused with this. Does that mean the variable (SQL) wont execute a char vector?

Answer 3

[Dan Howard]

Managed to find the solution.

For the line...

if true
  % where table_no = ''1234'''
end

Forgot you have to use double quotes.