# \#queryverse

**URL:** https://discourse.julialang.org/tag/queryverse/829.md

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

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## [Using an SQLite table as a Query.jl data source (or, best way to left-join a DataFrame or Vector with a very large sqlite table)](https://discourse.julialang.org/t/using-an-sqlite-table-as-a-query-jl-data-source-or-best-way-to-left-join-a-dataframe-or-vector-with-a-very-large-sqlite-table/116410)

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**Author:** [@sleak](https://discourse.julialang.org/u/sleak)\
**Replies:** 2\
**Last updated:** [July 3, 2024, 10:50pm UTC](https://discourse.julialang.org/t/using-an-sqlite-table-as-a-query-jl-data-source-or-best-way-to-left-join-a-dataframe-or-vector-with-a-very-large-sqlite-table/116410 "2024-07-03T22:50:24Z")

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I have a vector (of strings) that I want to left-join with an SQLite table (to find an “id” corresponding to each string). The SQLite table is too big to load into memory - but the left join should return only as many ro…

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## [Basic function usage in Query @filter](https://discourse.julialang.org/t/basic-function-usage-in-query-filter/114642)

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**Author:** [@seadoo](https://discourse.julialang.org/u/seadoo)\
**Replies:** 9\
**Last updated:** [May 23, 2024, 9:04pm UTC](https://discourse.julialang.org/t/basic-function-usage-in-query-filter/114642 "2024-05-23T21:04:00Z")

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Is the @filter macro from Query.jl only useful for simple things like \_.a \> 1 and so on? I’ve tried to use ismissing which just returns a boolean and it does not return anything (but also does not return any errors). Br…

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## [Dynamic selection of columns Query.jl](https://discourse.julialang.org/t/dynamic-selection-of-columns-query-jl/79526)

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**Author:** [@davide-f](https://discourse.julialang.org/u/davide-f)\
**Replies:** 4\
**Last updated:** [October 16, 2023, 2:56pm UTC](https://discourse.julialang.org/t/dynamic-selection-of-columns-query-jl/79526 "2023-10-16T14:56:25Z")

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Dear Community, I am trying to dynamically select columns using Query.jl like in the following script, but I am unable to do so. Any ideas? Thank you list\_cols = \[“col1”, “col2”…\] select = df |\> @select(∈(list\_cols)…

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## [Lifting function in Query.jl](https://discourse.julialang.org/t/lifting-function-in-query-jl/96599)

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**Author:** [@myrddin89](https://discourse.julialang.org/u/myrddin89)\
**Replies:** 2\
**Last updated:** [March 25, 2023, 6:17pm UTC](https://discourse.julialang.org/t/lifting-function-in-query-jl/96599 "2023-03-25T18:17:19Z")

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I’m having troubles using the lifting functionality in Query.jl and DataValues.jl with dot syntax. If I simply try the following using DataValues a = DataValue(0.4) a .\* 2 I get the this error: ERROR: MethodError: no…

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## [Query.jl, referencing \`\_.key\` in \`@groupby |\> @map\`](https://discourse.julialang.org/t/query-jl-referencing-key-in-groupby-map/17318)

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**Author:** [@leethargo](https://discourse.julialang.org/u/leethargo)\
**Replies:** 7\
**Last updated:** [January 22, 2022, 11:19pm UTC](https://discourse.julialang.org/t/query-jl-referencing-key-in-groupby-map/17318 "2022-01-22T23:19:14Z")

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I followed the recording of the Queryverse tutorial at JuliaCon by @davidanthoff and now get errors when I use similar queries. In particular, I want to use the \_.key shortcut in this query (see full example): data |\> …

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## [Unable to load Queryverse](https://discourse.julialang.org/t/unable-to-load-queryverse/69539)

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**Author:** [@PAHH](https://discourse.julialang.org/u/PAHH)\
**Replies:** 0\
**Last updated:** [October 11, 2021, 4:59am UTC](https://discourse.julialang.org/t/unable-to-load-queryverse/69539 "2021-10-11T04:59:46Z")

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Hi all, I’m using Julia 1.6.3 (VS Code 1.61.0) and am unable to use the Queryverse package. I first tried to load it onto my current environment (which also contains StatsKit among other things), but then I tried to load…

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## [Queryverse \`load(f) ▷ @take(3)\` appears to read the whole file](https://discourse.julialang.org/t/queryverse-load-f-take-3-appears-to-read-the-whole-file/63272)

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**Author:** [@dereksz](https://discourse.julialang.org/u/dereksz)\
**Replies:** 2\
**Last updated:** [August 3, 2021, 6:28pm UTC](https://discourse.julialang.org/t/queryverse-load-f-take-3-appears-to-read-the-whole-file/63272 "2021-08-03T18:28:13Z")

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Just watched David Anthoff’s awsome Introduction to the Queryverse video. David emphasises that the Queryverse is designed to work in a “streaming” fashion, and that data is supposed to be “pulled” through the stages in…

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## [Incompatibility Queryverse / DataFrames?](https://discourse.julialang.org/t/incompatibility-queryverse-dataframes/51822)

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**Author:** [@tlorans](https://discourse.julialang.org/u/tlorans)\
**Replies:** 2\
**Last updated:** [December 14, 2020, 7:28pm UTC](https://discourse.julialang.org/t/incompatibility-queryverse-dataframes/51822 "2020-12-14T19:28:58Z")

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Hello, I try to use simultaneously Queryverse and DataFrames packages, but it seems there is some incompatibility: julia\> Pkg.add("Queryverse") Updating registry at \`~/.julia/registries/General\` ####################…

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## [Queryverse queries lose type information?](https://discourse.julialang.org/t/queryverse-queries-lose-type-information/40572)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 8\
**Last updated:** [June 1, 2020, 9:17pm UTC](https://discourse.julialang.org/t/queryverse-queries-lose-type-information/40572 "2020-06-01T21:17:47Z")

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I’m working on a tutorial and have the following code: dflong2 = DataFrame(dflong |\> @mutate(year = tryparse(Int,String(\_.variable)\[end-3:end\]))) obviously I’m modifying the year column to be the result of trying to p…

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## [Queryverse: How to @select columns with specific eltype? (using \`oftype\` function)](https://discourse.julialang.org/t/queryverse-how-to-select-columns-with-specific-eltype-using-oftype-function/28709)

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**Author:** [@Anselm\_Jeong](https://discourse.julialang.org/u/Anselm_Jeong)\
**Replies:** 3\
**Last updated:** [September 14, 2019, 10:14am UTC](https://discourse.julialang.org/t/queryverse-how-to-select-columns-with-specific-eltype-using-oftype-function/28709 "2019-09-14T10:14:47Z")

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Dear all Queryverse users. In an auxilary package QueryOperators.NamedTupleUtilities, there is a helper function named oftype. I guess it is related with selecting columns with specific eltype. But I cannot figure out h…

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## [Metaprogramming Queryverse/Query Pipelines](https://discourse.julialang.org/t/metaprogramming-queryverse-query-pipelines/27032)

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**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 7\
**Last updated:** [July 31, 2019, 1:47pm UTC](https://discourse.julialang.org/t/metaprogramming-queryverse-query-pipelines/27032 "2019-07-31T13:47:53Z")

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Hello, I haven’t done any real metaprogramming yet (other than tinkering around with it) and I have a situation that I think could be a good fit for a metaprogramming solution. I’m working with a dataset in Queryverse a…

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## [Queryverse has a new homepage](https://discourse.julialang.org/t/queryverse-has-a-new-homepage/20985)

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**Author:** [@davidanthoff](https://discourse.julialang.org/u/davidanthoff)\
**Replies:** 6\
**Last updated:** [February 21, 2019, 7:57pm UTC](https://discourse.julialang.org/t/queryverse-has-a-new-homepage/20985 "2019-02-21T19:57:05Z")

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Queryverse now has its own homepage: https://www.queryverse.org/. The page mainly serves as a central landing place that highlights all the packages that constitute the Queryverse, plus it hosts all the documentation fo…

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## [Queryverse @map question](https://discourse.julialang.org/t/queryverse-map-question/12484)

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**Author:** [@johann.spies](https://discourse.julialang.org/u/johann.spies)\
**Replies:** 3\
**Last updated:** [July 20, 2018, 12:17am UTC](https://discourse.julialang.org/t/queryverse-map-question/12484 "2018-07-20T00:17:04Z")

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I have describe(gewig) Summary Stats: Mean: 2979.413793 Minimum: 1613.000000 1st Quartile: 2226.500000 Median: 2822.500000 3rd Quartile: 3618.250000 Maximum: 5140.000000 Length: …

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## [Intro to the Queryverse, a Julia data science stack - tutorial this Thursday](https://discourse.julialang.org/t/intro-to-the-queryverse-a-julia-data-science-stack-tutorial-this-thursday/11599)

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**Author:** [@xorJane](https://discourse.julialang.org/u/xorJane)\
**Replies:** 2\
**Last updated:** [June 15, 2018, 5:10am UTC](https://discourse.julialang.org/t/intro-to-the-queryverse-a-julia-data-science-stack-tutorial-this-thursday/11599 "2018-06-15T05:10:55Z")

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Hey everyone, @davidanthoff’s tutorial on the Queryverse will stream at this Thursday (June 14) at 9:30AM PDT/12:30PM EDT/18:30 CET/10:00PM IST! This one will cover Queryverse.jl, a Julia meta package off…

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## [Table transformation in JuliaDB or Queryverse or DataFramesMeta?](https://discourse.julialang.org/t/table-transformation-in-juliadb-or-queryverse-or-dataframesmeta/11622)

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**Author:** [@dmbates](https://discourse.julialang.org/u/dmbates)\
**Replies:** 5\
**Last updated:** [June 13, 2018, 1:47pm UTC](https://discourse.julialang.org/t/table-transformation-in-juliadb-or-queryverse-or-dataframesmeta/11622 "2018-06-13T13:47:34Z")

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I have been experimenting with different NLopt optimizers on particular examples of models from MixedModels. The current set of results is available at https://github.com/dmbates/MixedModelExamples/blob/master/results/…