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From:Ken Smith Date:April 6 2009 12:03pm
Subject:Conditional insert of NULL
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Hi
Sorry if this sounds like my previous NaN question, but it's not quite the same...
I want to conditionally insert null values into a table, but I'm getting zeros inserted,
not nulls.
I mistakenly thought I could initialise my variable to your defined mysqlpp::null value
and then set it based on my threshold value.
SSQLS looked like a nice solution until I discovered that I can't have more than 25
columns (feel free to correct me if I'm wrong - which is highly possible!).  Many of my
tables have much more than 25 columns.


Here's a piece of code with my simplistic approach...

mysqlpp::Null myfloatfield(mysqlpp::null);
if (condition)   myfloatfield = 10.0;
try {    Connection conn(false);    conn.connect("db", "localhost", "user", "password");  
 Query query = conn.query();
    query << "INSERT INTO test_float " << "VALUES ("          << "\""
<< myfloatfield << "\""           << ");";

    query.execute();...etc
mysql> select * from test_float;+------+| id   |+------+|    0 |
+------+
1 row in set (0.00 sec)

I know I can insert "null" as part of the query, but I need to do this conditionally
without having to construct multiple queries.
Thanks in advance,
Ken



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Thread
Conditional insert of NULLKen Smith6 Apr
  • RE: Conditional insert of NULLKen Smith6 Apr
    • RE: Conditional insert of NULLKen Smith6 Apr
      • RE: Conditional insert of NULLKen Smith6 Apr
  • Re: Conditional insert of NULLWarren Young6 Apr