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Trino is an open-source distributed SQL query engine designed to query large data sets distributed over one or more heterogeneous data sources. [1] Trino can query data lakes that contain a variety of file formats such as simple row-oriented CSV and JSON data files to more performant open column-oriented data file formats like ORC or Parquet [2] [3] residing on different storage systems like ...
A common table expression, or CTE, (in SQL) is a temporary named result set, derived from a simple query and defined within the execution scope of a SELECT, INSERT, UPDATE, or DELETE statement. CTEs can be thought of as alternatives to derived tables ( subquery ), views , and inline user-defined functions.
With the same table, the query SELECT C1 FROM T will result in the elements from the column C1 of all the rows of the table being shown. This is similar to a projection in relational algebra , except that in the general case, the result may contain duplicate rows.
mw-collapsible also does not require a header row in the table, as collapsible did. Tables will show the "[hide]" / "[show]" controls in the first row of the table (whether or not it is a header row), unless a table caption is present.(see § Tables with captions) Example with a header row
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
input_lines = LOAD '/tmp/my-copy-of-all-pages-on-internet' AS (line: chararray);-- Extract words from each line and put them into a pig bag-- datatype, then flatten the bag to get one word on each row words = FOREACH input_lines GENERATE FLATTEN (TOKENIZE (line)) AS word; -- filter out any words that are just white spaces filtered_words = FILTER words BY word MATCHES '\\w+';-- create a group ...
A data control language (DCL) is a syntax similar to a computer programming language used to control access to data stored in a database (authorization).In particular, it is a component of Structured Query Language (SQL).
In computing, Microsoft's ActiveX Data Objects (ADO) comprises a set of Component Object Model (COM) objects for accessing data sources. A part of MDAC (Microsoft Data Access Components), it provides a middleware layer between programming languages and OLE DB (a means of accessing data stores, whether databases or not, in a uniform manner).