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KDB-X Documentation

Home
Home
Guides
Guides
- Overview
- Brief introduction to q and KDB-X
- General Guidance
  General Guidance
  - Use the q Terminal (REPL)
- Basics
  Basics
- Querying
  Querying
- I/O and Communication
  I/O and Communication
- Performance Tips
- Interact with Databases
  Interact with Databases
  - Tables in the Filesystem
  - Types of Persisted Tables
    Types of Persisted Tables
    
    Serializing as an Object
    
    Splayed Tables
    
    Partitioned Tables
    
    Segmented Databases
  - Loading from Large Files
  - Relationships Between Tables
    Relationships Between Tables
    
    Foreign Keys
    
    Linking Columns
  - Maintenance
    Maintenance
    
    Data-At-Rest Encryption
    
    File Compression
    
    Time-Series Simplification
    
    Working with Sym Files
- Manage Streaming Data
  Manage Streaming Data
- Working With Code
  Working With Code
  - How to Debug
- Support a KDB-X system
  Support a KDB-X system
  - Handle Long Running Queries
  - Check Memory Usage
- Ingest Bloomberg Data
- Handle FIX Message Format
- Parallel Processing
- KDB-X Python
- Examples
  Examples
- Q for Mortals
  Q for Mortals
- Tutorials
- Glossary
Reference
Reference
- Reference Card for KDB-X and q
- q Reference
  q Reference
  - By topic
  - Phrasebook
    Phrasebook
    
    Introduction
    
    Index
    
    Arithmetic
    
    Casting
    
    Execution
    
    Finance
    
    Find
    
    Flags
    
    Format
    
    Geometry
    
    Indexes
    
    Math
    
    Matrixes
    
    Miscellaneous
    
    Parts and items
    
    Polynomials
    
    Rank
    
    Shape
    
    Sort
    
    Statistics
    
    Strings
    
    Temporal
    
    Tests
    
    Text
    
    phrases.q
    
    on style
    
    index to QIdioms
    
    QIdioms
  - Iteration
    Iteration
    
    Overview
    
    Implicit iteration
    
    Iterators
    
    Maps
    
    Accumulators
    
    Guide to iterators
  - Keywords
    Keywords
    
    abs
    
    aj, aj0, ajf, ajf0
    
    all, any
    
    and
    
    asc, iasc, xasc
    
    asof
    
    attr
    
    avg, avgs, mavg, wavg
    
    bin, binr
    
    ceiling
    
    count, mcount
    
    cols, xcol, xcols
    
    cor
    
    cos, acos
    
    cov, scov
    
    cross
    
    csv
    
    cut
    
    delete
    
    deltas
    
    desc, idesc, xdesc
    
    dev, mdev, sdev
    
    differ
    
    distinct
    
    div
    
    dsave
    
    each, peach
    
    ej
    
    ema
    
    enlist
    
    eval, reval
    
    except
    
    exec
    
    exit
    
    exp, xexp
    
    fby
    
    fills
    
    first, last
    
    fkeys
    
    flip
    
    floor
    
    get, set
    
    getenv, setenv
    
    group
    
    gtime, ltime
    
    hcount
    
    hdel
    
    hopen, hclose
    
    hsym
    
    ij, ijf
    
    in
    
    insert
    
    inter
    
    inv
    
    key
    
    keys, xkey
    
    like
    
    lj, ljf
    
    load, rload
    
    log, xlog
    
    lower
    
    lsq
    
    max, maxs, mmax
    
    md5
    
    med
    
    meta
    
    min, mins, mmin
    
    mmu
    
    mod
    
    neg
    
    next, prev, xprev
    
    not
    
    null'
    
    or
    
    over, scan
    
    parse
    
    pj
    
    prd, prds
    
    prior
    
    rand
    
    rank
    
    ratios
    
    raze
    
    read0
    
    read1
    
    reciprocal
    
    reverse
    
    rotate
    
    save, rsave
    
    select
    
    show
    
    signum
    
    sin, asin
    
    sqrt
    
    ss, ssr
    
    string
    
    sublist
    
    sum, sums, msum, wsum
    
    sv
    
    system
    
    tables
    
    tan, atan
    
    til
    
    trim, ltrim, rtrim
    
    type
    
    uj, ujf
    
    union
    
    ungroup
    
    update
    
    upsert
    
    use
    
    value
    
    var, svar
    
    view, views
    
    vs
    
    where
    
    within
    
    wj, wj1
    
    xbar
    
    xgroup
    
    xrank
  - Operators
    Operators
    
    Add
    
    Amend
    
    Apply, Index, Trap
    
    Assign
    
    Cast
    
    Coalesce
    
    Compose
    
    cut
    
    Deal, Roll, Permute
    
    delete
    
    Display
    
    Dict
    
    Divide
    
    Dynamic Load
    
    Drop
    
    Enkey, Unkey
    
    Enumerate
    
    Enumeration
    
    Enum Extend
    
    Equal
    
    exec
    
    File Binary
    
    File Text
    
    fills
    
    Find
    
    Flip Splayed
    
    Greater
    
    Greater Than
    
    Identity, Null
    
    Join
    
    Less Than
    
    Lesser
    
    Match
    
    mmu
    
    Multiply
    
    Not Equal
    
    Pad
    
    select
    
    Set Attribute
    
    Simple Exec
    
    Signal
    
    Subtract
    
    Take
    
    Tok
    
    update
    
    Vector Conditional
  - Control constructs
    Control constructs
    
    Cond
    
    do
    
    if
    
    while
  - Namespaces
    Namespaces
    
    .h
    
    .j
    
    .m
    
    .Q
    
    .z
  - Overloaded glyphs
  - Application
  - Atomic functions
  - Comparison
  - Conformability
  - Connection handles
  - Command-line options
  - Datatypes
  - Dictionaries
  - Enumerations
  - Evaluation control
  - Exposed infrastructure
  - File system
  - Function notation
  - Internal functions
  - Joins
  - Mathematics
  - Metadata
  - Namespaces
  - Parse trees
  - Parse trees
  - QSQL
    QSQL
    
    QSQL queries
    
    Functional qSQL
  - Regular Expressions
  - Syntax
  - System commands
  - Tables
  - Variadic syntax
  - Errors
  - Temporal data
  - Precision
  - Multithreaded input
  - Multithreaded primitives
  - KDB-X tick
    KDB-X tick
    
    Tickerplant (tick.q)
    
    Tickerplant pub/sub (u.q)
    
    RDB (r.q)
- AI Libraries
  AI Libraries
  - Overview
  - Vector Search
    Vector Search
    
    Brute Force (Flat)
    
    Hierarchical Navigable Small Worlds (HNSW)
    
    Inverted File (IVF)
    
    Inverted File Product Quantization (IVFPQ)
    
    Best Matching 25 (BM25)
    
    Fuzzy Matching
    
    Hybrid Search
  - Time Series Search
    Time Series Search
    
    Time Series Search (TSS)
    
    Dynamic Time Warping (DTW)
    
    Anomaly Detection
- Languages
  Languages
  - q
  - KDB-X Python
  - C/C++
  - C API for KDB-X
  - C#
  - Foreign Function Interface (FFI)
  - Java
  - R
  - Rust
Modules
Modules
- Modules Overview
- Module Framework
  Module Framework
  - About
  - Quickstart
- Parquet
  Parquet
  - Overview
  - Quickstart
- AI Libraries
  AI Libraries
- Object Storage
  Object Storage
  - About
  - Quickstart
  - Caching
  - Examples
  - Reference
- SQL
  SQL
  - About
  - Quickstart
  - Reference
  - Examples
- Kurl
  Kurl
  - About
  - Quickstart
  - Workflows
  - Reference
- Rest Server
  Rest Server
  - About
  - Quickstart
  - Examples
  - Reference
- Open Source Modules
  Open Source Modules
  - Logging
  - Fusionx
  - BLAS
  - PCRE2
  - Printf
Integrations
Integrations
- Overview
- Model Context Protocol (MCP) Server
- Visualization
  Visualization
  - Dashboards
- PG Wire (Postgres SQL Interface)
  PG Wire (Postgres SQL Interface)
  - About
  - Quickstart
  - Reference
  - Examples
- Vendor Integrations
  Vendor Integrations
  - Amazon Web Services
    Amazon Web Services
    
    AWS Overview
    
    Reference architecture
    
    Migrating KDB-X HDB to Amazon EC2
    
    AWS Lambda
  - Microsoft Azure
  - Google Cloud
Help and Support
Help and Support
- Support guide
- Resources
  Resources
Releases
Releases

`and`

Lesser of two values, logical AND

and is a multithreaded primitive.

asc, iasc, xasc

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