The WHERE clause restrictions depend on the type of statement, type of column, and whether a secondary index is used. For SELECT statements on partition keys, either all keys must be restricted or none. Clustering columns cannot be restricted if preceding ones are not. Secondary indexes allow restricting columns not in the primary key.

1. A deep look at the CQL WHERE clause

2. CQL WHERE clause
2© 2015. All Rights Reserved.
Driver
The WHERE clause restrictions are dependent on:
• The type of statement: SELECT, UPDATE or DELETE
• The type of column: partition key, clustering or regular column
• If a secondary index is used or not

3. 3© 2015. All Rights Reserved.
Driver
SELECT statements

4. Partition key restrictions
4© 2015. All Rights Reserved.
Driver
Cluster Date Time Count
‘cluster 1’ ‘2015-09-21’ ‘12:00’ 251
‘cluster 1’ ‘2015-09-22’ ‘12:00’ 342
‘cluster 2’ ‘2015-09-21’ ‘12:00’ 403
‘cluster 2’ ‘2015-09-22’ ‘12:00’ 451
CREATE TABLE numberOfRequests (
cluster text,
date text,
time text,
count int,
PRIMARY KEY ((cluster, date))
)
Partition Key

5. Partition key restrictions
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Driver
Cluster Date Murmur3 hash
‘cluster 1’ ‘2015-09-21’ -4782752162231423249
‘cluster 1’ ‘2015-09-22’ 4936127188075462704
‘cluster 2’ ‘2015-09-21’ 5822105674898716412
‘cluster 2’ ‘2015-09-22’ 2698159220916609751
A
C
D B
4611686018427387904
to
9223372036854775807
-9223372036854775808
to
-4611686018427387903
-1
to
4611686018427387903
-4611686018427387904
to
-1

6. Partition key restrictions
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Driver
Cluster Date Node
‘cluster 1’ ‘2015-09-21’ A
‘cluster 1’ ‘2015-09-22’ D
‘cluster 2’ ‘2015-09-21’ D
‘cluster 2’ ‘2015-09-22’ C
A
C
D B

7. Partition key restrictions
7© 2015. All Rights Reserved.
Driver
A
C
D B
SELECT * FROM numberOfRequests;
Driver

8. Partition key restrictions
8© 2015. All Rights Reserved.
Driver
SELECT * FROM numberOfRequests WHERE cluster= ‘cluster 1’;
InvalidRequest: code=2200 [Invalid query]
message="Partition key parts: date must be restricted as other parts are"

9. Partition key restrictions
9© 2015. All Rights Reserved.
Driver
A
C
D B
SELECT * FROM numberOfRequests WHERE cluster= ‘cluster 1’
AND date = ‘2015-09-21’;
Driver

10. Partition key restrictions
10© 2015. All Rights Reserved.
Driver
A
C
D B
SELECT * FROM numberOfRequests WHERE cluster= ‘cluster 1’
AND date = ‘2015-09-21’;
Driver
…with TokenAwarePolicy

11. Partition key restrictions
11© 2015. All Rights Reserved.
Driver
A
C
D B
SELECT * FROM numberOfRequests WHERE cluster= ‘cluster 2’
AND date IN (‘2015-09-21’, ‘2015-09-22’);
Driver

12. Partition key restrictions
12© 2015. All Rights Reserved.
Driver
A
C
D B
SELECT * FROM numberOfRequests WHERE cluster = ‘cluster 2’
AND date = ‘2015-09-21’;
Driver
…with TokenAwarePolicy
and asynchronous calls
SELECT * FROM numberOfRequests WHERE cluster = ‘cluster 2’
AND date = ‘2015-09-22’;

13. Partition key restrictions
13© 2015. All Rights Reserved.
Driver
SELECT * FROM numberOfRequests WHERE cluster= ‘cluster 1’
AND date >= ‘2015-09-21’;
InvalidRequest: code=2200 [Invalid query]
message="Only EQ and IN relation are supported on the partition key (unless
you use the token() function)"

14. Partition key restrictions
14© 2015. All Rights Reserved.
Driver
Cluster Date Node
‘cluster 1’ ‘2015-09-21’ A
‘cluster 1’ ‘2015-09-22’ D
‘cluster 2’ ‘2015-09-21’ D
‘cluster 2’ ‘2015-09-22’ C
A
C
D B
SELECT * FROM numberOfRequests WHERE cluster= ‘cluster 1’
AND date >= ‘2015-09-21’;

15. Partition key restrictions
15© 2015. All Rights Reserved.
Driver
• Murmur3Partitioner (default): uniformly distributes data across
the cluster based on MurmurHash hash values.
• RandomPartitioner: uniformly distributes data across the
cluster based on MD5 hash values.
• ByteOrderedPartitioner: keeps an ordered distribution of data
lexically by key bytes

16. Partition key restrictions
16© 2015. All Rights Reserved.
Driver
SELECT * FROM numberOfRequests
WHERE token(cluster, date) > token(‘cluster 1’, ‘2015-09-21’)
AND token(cluster, date) < token(‘cluster 1’, ‘2015-09-23’);

17. Partition key restrictions (SELECT)
17© 2015. All Rights Reserved.
• Without secondary index, either all partition key components must be
restricted or none of them
• = restrictions are allowed on any partition key component
• IN restrictions are allowed on any partition key component since 2.2
• Prior to 2.2, IN restrictions were only allowed on the last partition key
component
• =, >, >=, <= and < restrictions are allowed with the token function

18. Clustering column restrictions
18© 2015. All Rights Reserved.
CREATE TABLE numberOfRequests (
cluster text,
date text,
datacenter text,
server inet,
time text,
count int,
PRIMARY KEY((cluster, date), datacenter, server, time))
…

19. Clustering column restrictions
19© 2015. All Rights Reserved.
…
Datacenter Server Time Count
Iowa 196.8.7.134 00:00 130
Iowa 196.8.7.134 00:01 125
Iowa 196.8.7.134 00:02 97
Iowa 196.8.7.135 00:00 178
Iowa 196.8.7.135 00:01 201
[Iowa, 196.8.7.134, 00:02, count] :
97
In the Memtables:
[Iowa, 196.8.7.134, 00:00, count] :
130
[Iowa, 196.8.7.134, 00:01, count] :
125
[Iowa, 196.8.7.135, 00:00, count] :
178
[Iowa, 196.8.7.135, 00:01, count] :
201
[Iowa, 196.8.7.134, 00:00, count] :
130
Cell name
Cell
Column name

20. Clustering column restrictions
20© 2015. All Rights Reserved.
…
Datacenter Server Time Count
Iowa 196.8.7.134 00:00 130
Iowa 196.8.7.134 00:01 125
Iowa 196.8.7.134 00:02 97
Iowa 196.8.7.135 00:00 178
Iowa 196.8.7.135 00:01 201
[Iowa, 196.8.7.134, 00:02, count] :
97
In the SSTables:
[Iowa, 196.8.7.134, 00:00, count] :
130
[Iowa, 196.8.7.134, 00:01, count] :
125
[Iowa, 196.8.7.135, 00:00, count] :
178
[Iowa, 196.8.7.135, 00:0
201
[Iowa, 196.8.7.134, 00:00, count] :
130
Cell name
Cell
Column name

21. Clustering column restrictions
21© 2015. All Rights Reserved.
…
[Iowa, 196.8.7.134, 00:02, count] :
97
In the Memtables:
[Iowa, 196.8.7.134, 00:00, count] :
130
[Iowa, 196.8.7.134, 00:01, count] :
125
[Iowa, 196.8.7.135, 00:00, count] :
178
[Iowa, 196.8.7.135, 00:01, count] :
201
SELECT * FROM numberOfRequests
WHERE cluster = ‘cluster1’ AND date =‘2015-09-21’
AND datacenter = ‘Iowa’ AND server = ‘196.8.7.135’ AND time = ‘00:00’;
[Iowa,196.8.7.135,00:00]

22. Clustering column restrictions
22© 2015. All Rights Reserved.
…
SELECT * FROM numberOfRequests
WHERE cluster = ‘cluster1’ AND date =‘2015-09-21’
AND datacenter = ‘Iowa’ AND server = ‘196.8.7.135’ AND time = ‘00:00’;
[Iowa,196.8.7.135,00:00]
…
[Iowa, 196.8.7.134, 00:02, count] :
97
In the SSTables:
[Iowa, 196.8.7.134, 00:00, count] :
130
[Iowa, 196.8.7.134, 00:01, count] :
125
[Iowa, 196.8.7.135, 00:00, count] :
178
[Iowa, 196.8.7.135, 00:0
201

23. Clustering column restrictions
23© 2015. All Rights Reserved.
[Iowa, 196.8.7.134, 00:02, count] :
97
In the Memtables:
[Iowa, 196.8.7.134, 00:00, count] :
130
[Iowa, 196.8.7.134, 00:01, count] :
125
[Iowa, 196.8.7.135, 00:00, count] :
178
[Iowa, 196.8.7.135, 00:01, count] :
201
SELECT * FROM numberOfRequests
WHERE cluster = ‘cluster1’ AND date =‘2015-09-21’
AND datacenter = ‘Iowa’ AND server = ‘196.8.7.135’;
[Iowa,196.8.7.135]

24. Clustering column restrictions
24© 2015. All Rights Reserved.
…
SELECT * FROM numberOfRequests
WHERE cluster = ‘cluster1’ AND date =‘2015-09-21’
AND datacenter = ‘Iowa’ AND server = ‘196.8.7.135’;
[Iowa,196.8.7.135]
…[Iowa, 196.8.7.134, 00:02, count] :
97
In the SSTables:
[Iowa, 196.8.7.134, 00:00, count] :
130
[Iowa, 196.8.7.134, 00:01, count] :
125
[Iowa, 196.8.7.135, 00:00, count] :
178
[Iowa, 196.8.7.135, 00:0
201

25. Clustering column restrictions
SELECT * FROM numberOfRequests
WHERE cluster = ‘cluster1’ AND date =‘2015-09-21’
AND time = ‘00:00’;
[?,?,00:00]
InvalidRequest: code=2200 [Invalid query]
message="PRIMARY KEY column "time" cannot be restricted as preceding
column "datacenter" is not restricted"

26. Clustering column restrictions
26© 2015. All Rights Reserved.
…
AND datacenter = ‘Iowa’
AND server IN (‘196.8.7.134’, ‘196.8.7.135’)
AND time = ‘00:00’;
In 2.2:
[Iowa,196.8.7.134,00:00]
[Iowa,196.8.7.135,00:00]
…[Iowa, 196.8.7.134, 00:02, count] :
97
In the SSTables:
[Iowa, 196.8.7.134, 00:00, count] :
130
[Iowa, 196.8.7.134, 00:01, count] :
125
[Iowa, 196.8.7.135, 00:00, count] :
178
[Iowa, 196.8.7.135, 00:0
201

27. Clustering column restrictions
27© 2015. All Rights Reserved.
…
AND datacenter = ‘Iowa’
AND server IN (‘196.8.7.134’, ‘196.8.7.135’)
AND time = ‘00:00’;
In 2.1:
InvalidRequest: code=2200 [Invalid query]
message="Clustering column "server" cannot be restricted by an IN relation"

28. Clustering column restrictions
28© 2015. All Rights Reserved.
= multi-column restriction:
(clustering1, clustering2, clustering3) = (?, ?, ?)
IN multi-column restriction:
(clustering1, clustering2, clustering3) IN ((?, ?, ?), (?, ?, ?))
Slice multi-column restriction:
(clustering1, clustering2, clustering3) > (?, ?, ?)
(clustering1, clustering2, clustering3) >= (?, ?, ?)
(clustering1, clustering2, clustering3) <= (?, ?, ?)
(clustering1, clustering2, clustering3) < (?, ?, ?)

29. Clustering column restrictions
29© 2015. All Rights Reserved.
…
AND datacenter = ‘Iowa’
AND (server, time) IN ((‘196.8.7.134’, ‘00:00’),
(‘196.8.7.135’, ‘00:00’));
In 2.1:
[Iowa,196.8.7.134,00:00]
[Iowa,196.8.7.135,00:00]
…[Iowa, 196.8.7.134, 00:02, count] :
97
In the SSTables:
[Iowa, 196.8.7.134, 00:00, count] :
130
[Iowa, 196.8.7.134, 00:01, count] :
125
[Iowa, 196.8.7.135, 00:00, count] :
178
[Iowa, 196.8.7.135, 00:0
201

30. Clustering column restrictions
30© 2015. All Rights Reserved.
…
AND datacenter = ‘Iowa’
AND server = ‘196.8.7.134’
AND time > ’00:00’;
from after [Iowa,196.8.7.134,00:00]
to end of [Iowa,196.8.7.134]
…[Iowa, 196.8.7.134, 00:02, count] :
97
In the SSTables:
[Iowa, 196.8.7.134, 00:00, count] :
130
[Iowa, 196.8.7.134, 00:01, count] :
125
[Iowa, 196.8.7.135, 00:00, count] :
178
[Iowa, 196.8.7.135, 00:0
201

31. Clustering column restrictions (SELECT)
31© 2015. All Rights Reserved.
• Without secondary index, a clustering column cannot be restricted if
one of the previous ones was not
• = restrictions (single and multi) are allowed on any clustering column
• IN restrictions (single and multi) are allowed on any clustering column
since 2.2
• Prior to 2.2, IN restrictions (single and multi) were only allowed on the
last clustering column or set of clustering columns
• >, >=, <=, < restrictions (single and multi) are only allowed on the last
restricted clustering column or set of clustering columns
• CONTAINS and CONTAINS KEY restrictions are only allowed on
indexed collections

32. Secondary index queries
32© 2015. All Rights Reserved.
CREATE TABLE numberOfRequests (
cluster text,
date text,
datacenter text,
server inet,
time text,
count int,
PRIMARY KEY((cluster, date), datacenter, server, time));
CREATE INDEX ON numberOfRequests (time);
…

33. Secondary index queries
33© 2015. All Rights Reserved.
CREATE INDEX ON numberOfRequests (time);
CREATE LOCAL TABLE numberOfRequests_time_idx (
time text,
cluster text,
date text,
datacenter text,
server inet,
PRIMARY KEY(time, cluster, date, datacenter, server);
…
Table Partition Key
Table remaining clustering columns

34. IDX-BIDX-D
IDX-C
IDX-A
Secondary index queries
34© 2015. All Rights Reserved.
Driver
A
C
D B
SELECT * FROM numberOfRequests WHERE time = ‘12:00’;
Driver

35. Secondary index queries
35© 2015. All Rights Reserved.
Driver
SELECT * FROM numberOfRequests WHERE time = ‘12:00’;
idx
SELECT * FROM numberOfRequests_time_idx
WHERE time = ‘12:00’;
Results (Primary Keys)
table
SELECT with full PK;
[For each]
Add to rows

36. Secondary index queries
36© 2015. All Rights Reserved.
Driver
SELECT * FROM numberOfRequests WHERE time >= ‘12:00’;
InvalidRequest: code=2200 [Invalid query]
message="PRIMARY KEY column "time" cannot be restricted as preceding
column "datacenter" is not restricted"
Direct queries on secondary index support only =, CONTAINS or CONTAINS
KEY restrictions.

37. Secondary index queries
37© 2015. All Rights Reserved.
Driver
SELECT * FROM numberOfRequests WHERE time = ‘12:00’
AND count >= 500 ALLOW FILTERING;
idx
SELECT * FROM numberOfRequests_time_idx
WHERE time = ‘12:00’;
Results (Primary Keys)
table
SELECT with full PK;
[For each]
Add to rows
[if count >= 500]

38. IDX-BIDX-D
IDX-C
IDX-A
Secondary index queries
38© 2015. All Rights Reserved.
Driver
A
C
D B
SELECT * FROM numberOfRequests
WHERE cluster = ‘cluster 1’ AND date = ‘2015-09-21’AND time = ‘12:00’;
Driver

39. Secondary index queries
39© 2015. All Rights Reserved.
Driver
SELECT * FROM numberOfRequests
WHERE cluster = ‘cluster 1’ AND date = ‘2015-09-21’ AND time = ‘12:00’;
idx
SELECT * FROM numberOfRequests_time_idx
WHERE time = ‘12:00’ AND cluster = ‘1’ AND
date = ‘2015-09-21’;
Results (Primary Keys)
table
SELECT with full PK
[For each]
Add to rows

40. 40© 2015. All Rights Reserved.
Driver
UPDATE/DELETE statements

41. UPDATE statements
41© 2015. All Rights Reserved.
Driver
In the UPDATE statements all the primary key columns must be restricted and
the only allowed restrictions are:
• Prior to 3.0:
• Single column = restriction on any partition key or clustering column
• Single column IN restriction on the last partition key column
• In 3.0:
• = and IN single column restrictions on any partition key column
• = and IN single or multi column restrictions on any clustering column

42. DELETE statements
42© 2015. All Rights Reserved.
Driver
Before 3.0, in the DELETE statements all the primary key columns must be
restricted and the only allowed restrictions were:
• Single column = restriction on any partition key or clustering column
• Single column IN restriction on the last partition key column

43. DELETE statements
43© 2015. All Rights Reserved.
Driver
Since 3.0:
• The partition key columns must be restricted by = or IN restrictions
• A clustering column might not be restricted if none of the following is
• Clustering columns can be restricted by:
• Single or multi column = restriction
• Single or multi column IN restriction
• Single or multi column >, >=, <=, < restriction

44. © 2015. All Rights Reserved. 44
Design your tables for the queries
you want to perform.

45. Thank you