MySQL infinite loop in a subquery? -


the following query results infinite loop:

select      *,     (select              t2.`value`                     `table` t2                     t2.`variable` = 'xxx'                 , t2.`read` = (select                      max(t1.`read`)                                     `table` t1                                     t1.`variable` = 'xxx'                         , unix_timestamp(t1.`read`) < (1401801648 - n.integers)                 )     )     (select          @n:=@n + 1 integers             mysql.help_relation, (select @n:=0) dum     limit 48) n

i need result 48 rows 48 different time ranges (in example 1401801648 minus {1..48}). each row should contain value depending on current time range. query on bottom these 48 ranges. query in middle needed find date newest entry older calculated timestamp (1401801648 - n.integers). upper query tells me value of row date query in middle.

when "n.integers" replaced number works fine.

without subquery (t2) query not in loop(?):

select      *,     (select              max(t1.`read`)                     `table` t1                     t1.`variable` = 'xxx'                 , unix_timestamp(t1.`read`) < (1401801648 - n.integers)     )     (select          @n:=@n + 1 integers             mysql.help_relation, (select @n:=0) dum     limit 48) n

an alternative method avoiding using variables:-

select sub1.a_cnt, t2.value table t2 inner join (     select sub1.a_timestamp, sub1.a_cnt, t1.variable, max(t1.read) max_timestamp         (         select (1401801648 - units.i + 10 * tens.i) a_cnt,(1401801648 - units.i + 10 * tens.i) a_timestamp                 (select 0 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) units,         (select 0 union select 1 union select 2 union select 3 union select 4 union select 5 union select 6 union select 7 union select 8 union select 9) tens         units.i + 10 * tens.i between 1 , 48     ) sub1     inner join table t1     , unix_timestamp(t1.read) < sub1.a_timestamp     t1.variable = 'xxx'     group sub1.a_timestamp ) sub2 on t2.read = sub2.max_timestamp , t2.variable = sub2.variable

this uses load of unioned queries getting constants generate numbers 0 9, cross joins against copy of , minor calulation numbers 0 99, clause narrow down range 1 48, , uses calculate timestamps required.

this joined against table max read date each timestamp / generated number.

the results of joined against table other details row (in case value column).

not tested gives idea.


Comments

Post a Comment

Popular posts from this blog

commonjs - How to write a typescript definition file for a node module that exports a function? -

consider, toml node module can use: // toml.d.ts declare module toml { export function parse(value:string):any; } declare module "toml" { export = toml; } then: /// <reference path="../../../../../defs/toml/toml.d.ts"/> import toml = require('toml'); toml.parse(...); however, node module export single function, such 'glob' ( https://github.com/isaacs/node-glob ). the node usage of module be: var glob = require("glob") glob("*.js", {}, callback(err, files) { ... }); you'd naively expect this: // glob.d.ts declare function globs(paths:string, options:any, callback:{(err:any, files:string[]):void; ...but because typescripts 'import' semantics bit strange, seems can use 'import .. = require()' statement alias modules . trying call: /// <reference path="../../../../../defs/glob/glob.d.ts"/> import blog = require('glob'); results in: error ts2072: mod
Read more

openid - Okta: Failed to get authorization code through API call -

i'm integrating okta own idp server using okta's api. i'm implementing authorization code flow following steps below: in own server, use /api/v1/authn endpoint sessiontoken. use sessiontoken obtain authorization calling endpoint: /oauth2/v1/authorize?client_id=" + clientid + "&sessiontoken=" + sessiontoken + "&response_type=code&response_mode=query&scope=openid&redirect_uri=" + redirecturl + "&state=evanyang&nonce=" it's supposed return response status code 302 , location header containing redirect url code value. however, keep getting response status code 200 , without location header, html body saying "you using unsupported browser." , "javascript disabled on browser." according api documentation: http://developer.okta.com/docs/api/resources/oidc.html#authentication-request , sessiontoken parameter sufficient this: an okta one-time sessiontoken. allows api-based
Read more

thorough guide for profiling racket code -

did googling ("racket profiling", "racket measure performance"), didn't find , there no examples in docs. did google "profile" search on htdp - no luck. (profile (f ...)) output isn't obvious other small snippets. ideally want python's python -m cprofile usage examples. when search "python profiling", both duckduckgo , google give top result: 26.4. python profilers . (although scanned quickly, seems more of reference "thorough usage guide" examples. if had else in mind, perhaps please link that?) the equivalent racket documentation be: profile: statistical profiler . a usage example: #lang racket (require profile) (profile-thunk (thunk (function-to-profile arg0 arg1) )) here (thunk e) convenience (lambda () e) . bigger example: #lang racket (module mod racket (provide f) (define (f) (for/list ([i 10000]) i))) (require (prefix-in mod: 'mod)) (define (f) (for ([i 10000
Read more