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我要SELECT DISTINCT
在 Cassandra 中,但我认为 Cassandra 不支持这些操作。我该怎么办 SELECT DISTINCT
在 Cassandra ?是否有可能?
最佳答案
CQL 3.1.1并且以后仅支持分区键的 DISTINCT 操作。
SELECT statement now allows listing the partition keys (using the DISTINCT modifier). See CASSANDRA-4536.
select_statement ::= SELECT [ JSON | DISTINCT ] ( select_clause | '*' )
FROM table_name
[ WHERE where_clause ]
[ GROUP BY group_by_clause ]
[ ORDER BY ordering_clause ]
[ PER PARTITION LIMIT (integer | bind_marker) ]
[ LIMIT (integer | bind_marker) ]
[ ALLOW FILTERING ]
select_clause ::= selector [ AS identifier ] ( ',' selector [ AS identifier ] )
selector ::= column_name
| term
| CAST '(' selector AS cql_type ')'
| function_name '(' [ selector ( ',' selector )* ] ')'
| COUNT '(' '*' ')'
where_clause ::= relation ( AND relation )*
relation ::= column_name operator term
'(' column_name ( ',' column_name )* ')' operator tuple_literal
TOKEN '(' column_name ( ',' column_name )* ')' operator term
operator ::= '=' | '<' | '>' | '<=' | '>=' | '!=' | IN | CONTAINS | CONTAINS KEY
group_by_clause ::= column_name ( ',' column_name )*
ordering_clause ::= column_name [ ASC | DESC ] ( ',' column_name [ ASC | DESC ] )*
关于select - 如何在 cassandra 中选择 DISTINCT,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/18246412/
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