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  2. Hierarchical and recursive queries in SQL - Wikipedia

    en.wikipedia.org/wiki/Hierarchical_and_recursive...

    Hierarchical and recursive queries in SQL. A hierarchical query is a type of SQL query that handles hierarchical model data. They are special cases of more general recursive fixpoint queries, which compute transitive closures. In standard SQL:1999 hierarchical queries are implemented by way of recursive common table expressions (CTEs).

  3. Aggregate function - Wikipedia

    en.wikipedia.org/wiki/Aggregate_function

    The input and output domains may be the same, such as for SUM, or may be different, such as for COUNT. Aggregate functions occur commonly in numerous programming languages, in spreadsheets, and in relational algebra. The listagg function, as defined in the SQL:2016 standard [2] aggregates data from multiple rows into a single concatenated string.

  4. Pivot table - Wikipedia

    en.wikipedia.org/wiki/Pivot_table

    Pivot table. A pivot table is a table of values which are aggregations of groups of individual values from a more extensive table (such as from a database, spreadsheet, or business intelligence program) within one or more discrete categories. The aggregations or summaries of the groups of the individual terms might include sums, averages ...

  5. Materialized view - Wikipedia

    en.wikipedia.org/wiki/Materialized_view

    Materialized view. In computing, a materialized view is a database object that contains the results of a query. For example, it may be a local copy of data located remotely, or may be a subset of the rows and/or columns of a table or join result, or may be a summary using an aggregate function. The process of setting up a materialized view is ...

  6. Select (SQL) - Wikipedia

    en.wikipedia.org/wiki/Select_(SQL)

    The SQL SELECT statement returns a result set of rows, from one or more tables. [ 1 ][ 2 ] A SELECT statement retrieves zero or more rows from one or more database tables or database views. In most applications, SELECT is the most commonly used data manipulation language (DML) command. As SQL is a declarative programming language, SELECT ...

  7. Lookup table - Wikipedia

    en.wikipedia.org/wiki/Lookup_table

    Lookup table. In computer science, a lookup table (LUT) is an array that replaces runtime computation with a simpler array indexing operation, in a process termed as direct addressing. The savings in processing time can be significant, because retrieving a value from memory is often faster than carrying out an "expensive" computation or input ...

  8. Relational database - Wikipedia

    en.wikipedia.org/wiki/Relational_database

    A relational database (RDB[1]) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. [2] A database management system used to maintain relational databases is a relational database management system (RDBMS). Many relational database systems are equipped with the option of using SQL (Structured Query Language ...

  9. Help:Creating tables - Wikipedia

    en.wikipedia.org/wiki/Help:Creating_tables

    The row number column created by Template:Static row numbers is not counted in these calculations. Fill in the "replace with" box with: $1[[$3]]$4. Then click "Replace all". The "m" number may be different if a table uses rowspan or colspan. If you want links for the first column the following will work with both compact and long table wikitext ...