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How to run large SQL statements on new lines

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Dan Howard
Dan Howard 2018-10-25
回答： Dan Howard 2018-10-26
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.

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采纳的回答

Guillaume
Guillaume 2018-10-25
编辑：Guillaume 2018-10-25
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.

更多回答（2 个）

Dan Howard
Dan Howard 2018-10-26
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?
Dan Howard
Dan Howard 2018-10-26
Managed to find the solution.
For the line...
if true
% where table_no = ''1234'''
end
Forgot you have to use double quotes.

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