Asked by: Odette Jungkunz
technology and computing databases

What is the use of explain in MySQL?

Last Updated: 2nd April, 2020

The EXPLAIN keyword is used throughout various SQL databases and provides information about how your SQL database executes a query. In MySQL, EXPLAIN can be used in front of a query beginning with SELECT , INSERT , DELETE , REPLACE , and UPDATE .

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In this manner, what is explain in MySQL?

The EXPLAIN statement provides information about how MySQL executes statements: EXPLAIN works with SELECT , DELETE , INSERT , REPLACE , and UPDATE statements. When EXPLAIN is used with an explainable statement, MySQL displays information from the optimizer about the statement execution plan.

Subsequently, question is, how do you use explain? The verb explain is not followed by object pronoun. It can't be followed by a pronoun like me, him, her, you or us that is the object of the verb, or the pronoun that receives the action of the verb. That's why “Can you explain me …?” is wrong. The verb explain has a very specific sentence pattern.

Besides, what is Key_len in MySQL explain?

mysql. According to MySQL website, the key_len column indicates the length of the key that MySQL decided to use. The length is NULL if the key column says NULL . Note that the value of key_len enables you to determine how many parts of a multiple-part key MySQL actually uses.

What is filtered in explain MySQL?

As described here in the MySQL docs: The filtered column indicates an estimated percentage of table rows that will be filtered by the table condition. That is, rows shows the estimated number of rows examined and rows × filtered / 100 shows the number of rows that will be joined with previous tables. As of MySQL 5.7.

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How do you explain database?

A database is a collection of information that is organized so that it can be easily accessed, managed and updated. Computer databases typically contain aggregations of data records or files, containing information about sales transactions or interactions with specific customers.

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What is query explain with example?

query by example. In database management systems, query by example (QBE) refers to a method of forming queries in which the database program displays a blank record with a space for each field. You can then enter conditions for each field that you want to be included in the query.

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How do I query in MySQL?

MySQL - Select Query
  1. You can use one or more tables separated by comma to include various conditions using a WHERE clause, but the WHERE clause is an optional part of the SELECT command.
  2. You can fetch one or more fields in a single SELECT command.
  3. You can specify star (*) in place of fields.

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Where can I find explain plan in MySQL?

To view a visual explain execution plan, execute your query from the SQL editor and then choose the Execution Plan tab in the query results tab. The execution plan defaults to "Visual Explain" but also has a "Tabular Explain" view that is similar to what you would see when executing EXPLAIN in the MySQL client.

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What are SQL commands?

SQL commands are instructions, coded into SQL statements, which are used to communicate with the database to perform specific tasks, work, functions and queries with data. Data Definition Language (DDL) - These SQL commands are used for creating, modifying, and dropping the structure of database objects.

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What do you mean by query?

A query is a request for data or information from a database table or combination of tables. This data may be generated as results returned by Structured Query Language (SQL) or as pictorials, graphs or complex results, e.g., trend analyses from data-mining tools.

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What is analyze in MySQL?

ANALYZE TABLE performs a key distribution analysis and stores the distribution for the named table or tables. For MyISAM tables, this statement is equivalent to using myisamchk --analyze. This statement requires SELECT and INSERT privileges for the table. ANALYZE TABLE works with InnoDB , NDB , and MyISAM tables.

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What is different between SQL and MySQL?

SQL stands for Structured Query Language. It's a standard language for accessing and manipulating databases. MySQL is a database management system, like SQL Server, Oracle, Informix, Postgres, etc. MySQL is an RDMS (Relational Database Management System).

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What is Filesort in MySQL?

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How do I query optimization in MySQL?

Even if you optimize your MySQL queries and fail to come up with a good database structure, your database performance can still halt when your data increases.
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How do I find the query plan in SQL Server?

Use SQL Server Profiler
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Can you explain me why?

So, when you ask "Can you explain it to me?", you are basically asking whether the opposite person is capable of explaining something. Could is a safe option and is more polite, so always go for could. By the way, it is explain to me (or better, explain it to me), not explain me.

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What is the meaning of example?

An example of something is a particular situation, object, or person which shows that what is being claimed is true. If you refer to a person or their behaviour as an example to other people, you mean that he or she behaves in a good or correct way that other people should copy.

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Is the a verb?

No; the word 'the' is not a verb. It is a determiner: specifically, the definite article. No. Verbs can be inflected for tense, and a verb always has a Subject preceding it.

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Can you explain me or to me?

Explain to me. "me" is the indirect object. Intransitive verbs don't have objects, direct or indirect; they have complements. The prepositional phrase to me (where "me" is the object of the preposition "to") is a complement that modifies (completes the meaning of) the intransitive verb explain.

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How do you explain something in an essay?

Give your reader a reason to learn about your concept. Connect this information to something they already know, or give them a definition which either reverses their expectations or gives a new perspective or insight. Give a clear definition. Explain any unfamiliar terms or special vocabulary.