Splunk SQL to SPL

In this section, we will introduce the user to the SPL (Search Processing Language) format and the various Splunk Search Commands styles. We also intend to help you determine which form of the command will better match your question. It will help you to understand the SPL and even its data types and use.

The Search Processing Language (SPL) has a wide range of search commands to choose from, which helps the user to perform a wide variety of different jobs. The Splunk platform allows its user to use an expansive processing language. This feature enables a user to reduce and convert a massive amount of data from a dataset into small pieces of information that are important and can be used to build reports.

It is not a perfect mapping between SQL and Splunk Search Processing Language (SPL), but if you're familiar with SQL, this fast comparison might be useful as a jump-start in using the search commands.

Concepts

No data is processed in a standard database by the Splunk platform. Instead, it stores data with an implicit time dimension, in a distributed, non-relational, semi-structured database. In the database world, however, there are analogs to many of the concepts.

From SQL to Splunk SPL

SQL is designed to search column-consisting relational database tables. The SPL is designed to scan for events consisting of fields. You often see examples in SQL which use "mytable" and "mycolumn." You'll see examples in SPL which relate to "fields." In these examples, the field "source" is used as a "table" proxy. "Source" is the name of the file, stream, or other input in Splunk from which a specific piece of data originates.

• The searches in Search Processing Language hard

ly require the FIELDS command to filter out columns in the Splunk, since the user interface provides a more convenient filtering method. The FIELDS command is used for parallelism in the SPL Examples.

• We need not to use the AND operator in boolean searches with SPL, because AND is implied in terms between. However, they must be specified in uppercase when you use the AND or OR operators.
• There's no need to define SPL commands in uppercase. The commands are specified in uppercase in those SPL examples for easier identification and clarity.

Data types

bool

The value of the < bool > argument represents the form of Boolean data. The 'real' or 'fake' documentation is stated. In commands, other combinations of Boolean values are accepted. For example, you can use 't,' 'T,' 'TRUE,' or the number one '1' for 'true' too. You can use 'f', 'F', 'FALSE' or the number zero '0' for 'false.'

int

The value of the argument < int > represents the type of integral data.

num

The argument value of < num > represents the type of a number of the data.

float

The value of the < float > argument represents the type of float data.

Common syntax clauses

bin-span

Syntax:

Description: Sets the size of each bin.

Example: span=2d

Example: span=5m

Example: span=10

by-clause

Syntax:

Description: Fields to group by.

For Example port, BY addr

The Search Processing Language has a wide range of search commands to choose from, which helps the user to perform a wide variety of different jobs. The Splunk platform provides an expansive processing language that allows a user to reduce and convert a massive amount of data from a dataset into small pieces of information that are important.

Splunk Search Pipeline

The "information pipeline" in the Splunk platform is a Splunk search structure that contains a set of commands delimited by the pipe character present in the keyboard.

The quest consists of commands that are piped to another command, which helps in the reduction and formulation of outcomes into something that the user needs.

At the beginning of the pipeline, a search for Splunk starts with search words. The keywords, boolean expressions, phrases, key/value pairs, etc. are the search terms that determine what events from the index(s) we want to retrieve from the database.

The collected events are then passed as inputs into a quest/search command, which uses a pipe character in the Splunk platform for better searching. It will further be converted into the results we need. The search command is inferred at the beginning of a search pipeline, even though we do not state it directly. So if we type: host="localhost "immediately, it will be completed as search host=" localhost. "

Fields

In the Splunk platform, results and events which flow through the Search pipeline exist as a series of fields that are derived from the data that are present in the platform. The fields contain value strings that are applicable to particular data events and could be used to filter data alongside search commands. At the time of searching, it can come from the Index. Also, it can be gathered from various sources such as event types, regex extractions, tags, etc. A field name may be present or absent for a given occurrence, where present it may include a single or multiple string values.

Some important fields include the index, time, host, source, and raw.

Some notable fields are:

Null: A field not present on a given result or event. For this field, specific events or outcomes in the same quest can have values.

Empty Field: An empty field is a field that consists of an empty value. It is termed as an empty string.

Empty value: An empty string value, or ". This can also be represented as a string of zero length.

Multivalue Fields: A area with a value greater than one. All fields that are non-null contain an ordered list of strings. The typical case is, this is a one-value list. It is a multivalue field if the list contains more than one entry.

Quotes and Escape Characters in Splunk

When there is a requiring assessment of the Whole string, then the quotes are used. Splunk needs quotes that include white spaces, commas, pipes, quotes, or brackets in field values. There must be a distinction between quotes.

The escape character (\) in the Splunk platform is used to escape from assessment quotes, pipes, and itself when used while searching a string.

SPL Components

There are a few components in the search while we are writing a Search processing Language, which is used to format or filter the data in the Splunk platform. The quests that are included in the SPL have a combination of the various component. Below is a list of the components.

Search Terms

To filter out what we want in our result, the terms of the searches have some specific keywords or sentences. In Splunk, the search terms can be anything we are interested in like they can be the name of the fields we want to search, maybe any indexes in which we are interested.

Commands

When we want to take some action on the results such as altering, formatting, renaming, sorting, etc. then we use commands. There's a variety of search commands we might use, and the rest of the blog will address more.

Functions

Search functions are used along with commands to determine what kind of computation is to be performed in specific fields. Typically functions are used alongside statistical instructions, for example, stats.

Clauses

Clauses help group or rename fields to help organize results in the document. Some common clauses are the "BY" clause, which sorts out the results by a certain field, the "AS" clause used to rename it, and the "WHERE" clause used to sort or filter the results.

Some useful clauses used in filtering outcomes include the "AND" and "OR" clauses, which are usually used for search terms to determine the words are to be included. If no clause is provided at the start of a search, the "AND" clause will be used automatically.

Arguments

The arguments in Splunk are either optional or necessary arguments. The arguments that are required to allow the commands to operate, and usually, if not given, return an error in the Splunk. The arguments contain either the name, the meaning, or the Boolean meaning of a field in the Splunk. The command argument contains a default value if, in any event, any value to the argument is not specified.

Sub-Searches

In Splunk platform, when a search is done, and then the quest searches its search, and after the search is completed, the result is sent to the parent command as an argument value, then this type of search is known as a sub-search. It is written in the square bracket, and it runs first before the command runs in the Splunk. Sub-searches are used when we need to filter out more data from our database, or we need to combine two searches.

Example: