Setting value to MySql

Jokke

Hello,

I made a simple table for testing. The table has 2 columns named A and B. The values are 1 and 2. The data is readable with both column based and row based query.

I used this statement for reading "SELECT A, B FROM deebee.Test LIMIT 0, 1000 ;"

How should the update statement look like? Any examples?

I tried some statements but they did nothing or caused the following alarm "Exception while setting point TestPoint: java.sql.SQLException: Parameter index out of range (1 > number of parameters, which is 0)."

Regards
Jokke

apl

Hi,

the SQL-Update syntax is

UPDATE tablenname
SET A=3, B=4
where A=1

Hope this helps

Arne

mlohbihler

Yeah, the documentation is a bit lite on the matter. You need a "?" parameter in your statement, where the parameter is value to which the point is being set.

For example, i created a table thus:

create table testTable ( c1 int, c2 int);

... and added a couple rows:

insert into testTable (c1, c2) values (1, 10), (2, 11)

Then, i created a data source with a row-based query:

select c1, c2 from testTable

... and a couple of points with row identifiers "1" and "2". On the second point i added this update statement:

update testTable set c2=? where c1=2

Then, when i go to the watchlist and set the point to "20" and then check the table contents, i see that the c2 value for the correct row is "20".

Hope this helps.

Jokke

Such a small thing but thanks it helped.

Is '??' used as escape if '?' is needed in the statement? In mysql, I think there should not be such need but just curiosity.

Regards
Jokke

mlohbihler

After years of using prepared statements in many databases, i have to admin i have no idea. It never came up.