Cfquery check null

By the way, you don't need the pound signs inside of an evaluation: only when using a variable as a literal such as when outputting. The method of grabbing all the student table records will work great when you have or so students.

What happens when it is put into production and there are 25, students? While the java class of CFQuery object coldfusion. QueryTable will return empty string for any null value, it's parent class coldfusion. Table is providing a method getField row, column to access the query table values directly, which return "undefined" if the value is null.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. How to check for a null value from the return value in ColdFusion query loop Ask Question. Asked 9 years, 11 months ago. But, the thread got me thinking about NULL values. I also know that NULL values are not used in ColdFusion and actually destroy the variable they are assigned to if, for example, they are returned from a Java method call.

This returns a single record which as a NULL value and an empty string. I then tried to run various query on that query:. The results surprised me a bit. But, point of fact, they do. They handle them correctly. I had also tested above to see if the NULL comparison would work on empty strings. It did not. Everything seems to work exactly as you would expect it to work in a regular SQL query. This is why it comes across as an empty string.

There is obviously a JavaCast happening somewhere under the hood. I have to say, I am fairly impressed with the ColdFusion query of queries. A timeout is useful in preventing requests that are running for more than the limit set. The timeout attribute sets the maximum number of seconds that each action of a query is allowed to execute before returning an error. The volume of traffic to your web site or applications impacts the performance of your site or application.

To enhance the performance, you can cache your database queries. A cached query is a query that has its results stored in the server's memory.

The results are stored when the query is first run. Whenever you run the query thereafter, ColdFusion retrieves the results from memory. You can also cache a query using the cachedWithin attribute with the CreateTimeSpan function. In the example below, if the query's cached data is older than 60 seconds, the query is re-run. Otherwise, the cached data is used. Legal Notices Online Privacy Policy. This tag is unsupported in CFFiddle.

See also. ColdFusion release : Added the attribute returnType. ColdFusion 9: Datasource attribute is optional now. ColdFusion 8: Added the result variable that specifies the ID of a row. ColdFusion MX 7: Added the result attribute for specifying an alternate name for the structure that holds the result variables. Added result variables for the SQL statement executed sql , the number of records returned recordcount , whether the query was cached cached , an array of cfqueryparam values sqlparameters , and the list of columns in the returned query columnlist.

Changed dot notation support: ColdFusion now supports dot notation within a record set name. ColdFusion interprets such a name as a structure. Deprecated the connectString, dbName, dbServer, provider, providerDSN , and sql attributes, and all values of the dbtype attribute except query.

They do not work, and might cause an error, in releases later than ColdFusion 5. New query object variable: cfquery. No longer supports native drivers. This ID can be used to either retrieve or remove query from cache cacheRegion Optional Cache region to be used to cache query result.

Applies only if dbtype is set to hql. This tag creates a query object, providing this information in query variables:. Ensures that the length check is done by ColdFusion before the string is sent to the DBMS, thereby helping to prevent the submission of malicious strings. For maximum validation of string data, specify the maxlength attribute.

This tag does the following:. For all other types, if the maxLength attribute is used, a data value cannot exceed the maximum length specified. ColdFusion debug output shows the bind variables as question marks and lists the values beneath the query, in order of usage.

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