我使用以下代码来创建表:
CREATE KEYSPACE mykeyspace
WITH REPLICATION = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 };
USE mykeyspace;
CREATE TABLE users (
user_id int PRIMARY KEY,
fname text,
lname text
);
INSERT INTO users (user_id, fname, lname)
VALUES (1745, 'john', 'smith');
INSERT INTO users (user_id, fname, lname)
VALUES (1744, 'john', 'doe');
INSERT INTO users (user_id, fname, lname)
VALUES (1746, 'john', 'smith');
我想找到独特的价值lname
列(不是主键)。我想得到以下结果:
lname
-------
smith
通过使用SELECT DISTINCT lname FROM users;
然而自从lname
不是一个PRIMARY KEY
我收到以下错误:
InvalidRequest: code=2200 [Invalid query] message="SELECT DISTINCT queries must
only request partition key columns and/or static columns (not lname)"
cqlsh:mykeyspace> SELECT DISTINCT lname FROM users;
我怎样才能从中获得不同的值lname
?