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Redis - How to store the result of zrange query as another ordered set
For example I create a sorted set with this command:
zadd key1 1 u1 2 u2 3 u3
Now I to query last 2 items and store under other key, say key2. I know that I need to query like this:
zrange key1 -2 -1
but I don't know how to store the result with key2. Sorry for noob question, I am new to Redis, just 2 hours :)
redis sortedset
asked Nov 21 '18 at 12:36
NarekNarek
18.2k55174310
add a comment |
For example I create a sorted set with this command:
zadd key1 1 u1 2 u2 3 u3
Now I to query last 2 items and store under other key, say key2. I know that I need to query like this:
zrange key1 -2 -1
but I don't know how to store the result with key2. Sorry for noob question, I am new to Redis, just 2 hours :)
redis sortedset
asked Nov 21 '18 at 12:36
NarekNarek
18.2k55174310
add a comment |
For example I create a sorted set with this command:
zadd key1 1 u1 2 u2 3 u3
Now I to query last 2 items and store under other key, say key2. I know that I need to query like this:
zrange key1 -2 -1
but I don't know how to store the result with key2. Sorry for noob question, I am new to Redis, just 2 hours :)
redis sortedset
asked Nov 21 '18 at 12:36
NarekNarek
18.2k55174310
For example I create a sorted set with this command:
zadd key1 1 u1 2 u2 3 u3
Now I to query last 2 items and store under other key, say key2. I know that I need to query like this:
zrange key1 -2 -1
but I don't know how to store the result with key2. Sorry for noob question, I am new to Redis, just 2 hours :)
redis sortedset
redis sortedset
asked Nov 21 '18 at 12:36
NarekNarek
18.2k55174310
asked Nov 21 '18 at 12:36
NarekNarek
18.2k55174310
asked Nov 21 '18 at 12:36
NarekNarek
18.2k55174310
asked Nov 21 '18 at 12:36
NarekNarek
18.2k55174310
asked Nov 21 '18 at 12:36
NarekNarek
18.2k55174310
18.2k55174310
add a comment |
add a comment |
1 Answer
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While Redis does not have a built-in command to do that, you can get away easily and safely with a Lua script. This one is a just a little extra tricky because the reply from ZRANGE needs swapping between the pairs of member-score to be used as input for ZADD.
local src, dst = KEYS[1], KEYS[2]
local from, to = ARGV[1], ARGV[2]
local payload = redis.call('ZRANGE', src, from, to, 'WITHSCORES')
for i = 1, #payload/2 do
payload[2*i-1], payload[2*i] = payload[2*i], payload[2*i-1]
end
return redis.call('ZADD', dst, unpack(payload))
For details on how to use Lua in Redis see the EVAL commmand.
answered Nov 21 '18 at 13:38
Itamar HaberItamar Haber
28.8k43760
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
While Redis does not have a built-in command to do that, you can get away easily and safely with a Lua script. This one is a just a little extra tricky because the reply from ZRANGE needs swapping between the pairs of member-score to be used as input for ZADD.
local src, dst = KEYS[1], KEYS[2]
local from, to = ARGV[1], ARGV[2]
local payload = redis.call('ZRANGE', src, from, to, 'WITHSCORES')
for i = 1, #payload/2 do
payload[2*i-1], payload[2*i] = payload[2*i], payload[2*i-1]
end
return redis.call('ZADD', dst, unpack(payload))
For details on how to use Lua in Redis see the EVAL commmand.
answered Nov 21 '18 at 13:38
Itamar HaberItamar Haber
28.8k43760
add a comment |
While Redis does not have a built-in command to do that, you can get away easily and safely with a Lua script. This one is a just a little extra tricky because the reply from ZRANGE needs swapping between the pairs of member-score to be used as input for ZADD.
local src, dst = KEYS[1], KEYS[2]
local from, to = ARGV[1], ARGV[2]
local payload = redis.call('ZRANGE', src, from, to, 'WITHSCORES')
for i = 1, #payload/2 do
payload[2*i-1], payload[2*i] = payload[2*i], payload[2*i-1]
end
return redis.call('ZADD', dst, unpack(payload))
For details on how to use Lua in Redis see the EVAL commmand.
answered Nov 21 '18 at 13:38
Itamar HaberItamar Haber
28.8k43760
add a comment |
While Redis does not have a built-in command to do that, you can get away easily and safely with a Lua script. This one is a just a little extra tricky because the reply from ZRANGE needs swapping between the pairs of member-score to be used as input for ZADD.
local src, dst = KEYS[1], KEYS[2]
local from, to = ARGV[1], ARGV[2]
local payload = redis.call('ZRANGE', src, from, to, 'WITHSCORES')
for i = 1, #payload/2 do
payload[2*i-1], payload[2*i] = payload[2*i], payload[2*i-1]
end
return redis.call('ZADD', dst, unpack(payload))
For details on how to use Lua in Redis see the EVAL commmand.
answered Nov 21 '18 at 13:38
Itamar HaberItamar Haber
28.8k43760
While Redis does not have a built-in command to do that, you can get away easily and safely with a Lua script. This one is a just a little extra tricky because the reply from ZRANGE needs swapping between the pairs of member-score to be used as input for ZADD.
local src, dst = KEYS[1], KEYS[2]
local from, to = ARGV[1], ARGV[2]
local payload = redis.call('ZRANGE', src, from, to, 'WITHSCORES')
for i = 1, #payload/2 do
payload[2*i-1], payload[2*i] = payload[2*i], payload[2*i-1]
end
return redis.call('ZADD', dst, unpack(payload))
For details on how to use Lua in Redis see the EVAL commmand.
answered Nov 21 '18 at 13:38
Itamar HaberItamar Haber
28.8k43760
answered Nov 21 '18 at 13:38
Itamar HaberItamar Haber
28.8k43760
answered Nov 21 '18 at 13:38
Itamar HaberItamar Haber
28.8k43760
answered Nov 21 '18 at 13:38
Itamar HaberItamar Haber
28.8k43760
28.8k43760
add a comment |
add a comment |
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