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Hi is there any way I can use != operator using CQL in Cassandra? I am trying to use a != operator on my columnfamily but when I try using that it says:

cqlsh:EPCContent> select * from "MediaCategoryGroup" where "MCategoryID"!=1;

I get this error:

Invalid syntax at line 1, char 55
  select * from "MediaCategoryGroup" where "MCategoryID"!=1;
                                                        ^
Aaron
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Gargee Banerjee
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2 Answers2

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If you look at the Cassandra SELECT syntax, you will see that the WHERE clause must be "composed of relations on the columns that are part of the PRIMARY KEY and/or have a secondary index defined on them." Does your column conform to that specification?

Just for your information this is the full list of relation operators: '=' | '<' | '>' | '<=' | '>=' | '!=' | IN | CONTAINS | CONTAINS KEY.

Colin Strong
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emgsilva
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  • But we can use "<" | ">" | "<=" | ">=" only if that field is a Primary key. – Gargee Banerjee Oct 15 '13 at 23:03
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    yes, in Cassandra you can only do that on primary key fields (also from composite keys) or "secondary indexes" and not all of them are possible all the times... – emgsilva Oct 15 '13 at 23:05
  • How would you do it to get all the rows where a specific field is not null? – David Torres Jun 13 '16 at 09:21
  • @DavidTorres I am not sure you will be able to do that directly on a Cassandra query. As mentioned you cannot use the "!=" operator (not sure if this has changed on recent versions of Cassandra). Furthermore, I believe the fields you can use in filtering/operators (part of primary key or composite key) all need to be different from null... So, most probably you need to perform a read of relevant elements and then do some other filtering on your application. – emgsilva Jun 15 '16 at 08:20
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Go with <> instead !=. It's working for me.

Gūrūđáttá Ákūlá
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