jon-wei commented on a change in pull request #9879:
URL: https://github.com/apache/druid/pull/9879#discussion_r428336359
##########
File path: docs/tutorials/tutorial-query.md
##########
@@ -24,56 +24,165 @@ sidebar_label: "Querying data"
-->
-This tutorial will demonstrate how to query data in Apache Druid, with
examples for Druid SQL and Druid's native query format.
+This tutorial demonstrates how to query data in Apache Druid using Druid SQL,
a SQL-like language
+for querying data in Druid.
-The tutorial assumes that you've already completed one of the 4 ingestion
tutorials, as we will be querying the sample Wikipedia edits data.
+It assumes that you've completed the [Quickstart](../tutorials/index.md)
+or one of the following tutorials, since we'll query datasources that you
would have created
+by following one of them:
* [Tutorial: Loading a file](../tutorials/tutorial-batch.md)
* [Tutorial: Loading stream data from Kafka](../tutorials/tutorial-kafka.md)
* [Tutorial: Loading a file using
Hadoop](../tutorials/tutorial-batch-hadoop.md)
-Druid queries are sent over HTTP.
-The Druid console includes a view to issue queries to Druid and nicely format
the results.
+There are various ways to run Druid SQL queries: from the Druid console, using
a command line utility
+and by posting the query by HTTP. We'll look at each of these.
-## Druid SQL queries
-Druid supports a dialect of SQL for querying.
+## Query SQL from the Druid console
-This query retrieves the 10 Wikipedia pages with the most page edits on
2015-09-12.
+The Druid console includes a view that makes it easier to build and test
queries, and
+view their results.
-```sql
-SELECT page, COUNT(*) AS Edits
-FROM wikipedia
-WHERE TIMESTAMP '2015-09-12 00:00:00' <= "__time" AND "__time" < TIMESTAMP
'2015-09-13 00:00:00'
-GROUP BY page
-ORDER BY Edits DESC
-LIMIT 10
-```
+1. Start up the Druid cluster, if it's not already running, and open the Druid
console in your web
+browser.
+
+2. Click **Query** from the header to open the Query view:
+
+ 
+
+ You can write queries directly in the edit pane, but we'll generate a
starter query
+ using query builder controls.
+
+3. Expand the wikipedia datasource tree in the left pane. We'll
+create a query for the page dimension.
+
+4. Click `page` and then **Show:page** from the menu:
+
+ 
+
+ A SELECT query appears in the query edit pane and immediately runs.
However, in this case, the query
+ returns no data, since by default the query filters for data from the last
day, while our data is considerably
+ older than that. Let's remove the filter.
+
+5. In the datasource tree, click `__time` and **Remove Filter**.
+
+ 
+
+6. Click **Run** to run the query.
+
+ You should now see two columns of data, a page name and the count:
+
+ 
+
+ Notice that the results are limited in the console to about a hundred, by
default, due to the **Smart query limit**
+ feature. This helps users avoid inadvertently running queries that return
an excessive amount of data, possibly
+ overwhelming their system.
+
+7. Let's edit the query directly and take a look at a few more query building
features in the editor.
+ Click in the query edit pane and make the following changes:
+
+ 1. Add a line after the first column, `"page"` and Start typing the name
of a new column, `"countryName"`. Notice that the autocomplete menu suggests
column names, functions, keywords, and more. Choose "countryName" and
+add the new column to the GROUP BY clause as well, either by name or by
reference to its position, `2`.
+
+ 2. For readability, replace `Count` column name with `Edits`, since the
`COUNT()` function actually
+returns the number of edits for the page. Make the same column name change in
the ORDER BY clause as well.
+
+ The `COUNT()` function is one of many functions available for use in
Druid SQL queries. You can mouse over a function name
+ in the autocomplete menu to see a brief description of a function. Also,
you can find more information in the Druid
+ documentation; for example, the `COUNT()` function is documented in
+ [Aggregation functions](../querying/sql.md#aggregation-functions).
+
+ The query should now be:
+
+ ```sql
+ SELECT
+ "page",
+ "countryName",
+ COUNT(*) AS "Edits"
+ FROM "wikipedia"
+ GROUP BY 1, 2
+ ORDER BY "Edits" DESC
+ ```
+
+ When you run the query again, notice that we're getting the new
dimension,`countryName`, but for most of the rows, its value
+ is null. Let's
+ show only rows with a `countryName` value.
+
+8. Click the countryName dimension in the left pane and choose the first
filtering option. It's not exactly what we want, but
+we'll edit it by hand. The new WHERE clause should appear in your query.
+
+8. Modify the WHERE clause to exclude results that do not have a value for
countryName:
+
+ ```sql
+ WHERE "countryName" IS NOT NULL
+ ```
+ Run the query again. You should now see the top edits by country:
+
+ 
-Let's look at the different ways to issue this query.
+9. Under the covers, every Druid SQL query is translated into a query in the
JSON-based _Druid native query_ format before it runs
+ on data nodes. You can view the native query for this query by clicking `...`
and **Explain SQL Query**.
-### Query SQL via the console
+ While you can use Druid SQL for most purposes, familiarity with native
query is useful for composing complex queries and for troubleshooting
+performance issues. For more information, see [Native
queries](../querying/querying.md).
-You can issue the above query from the console.
+ 
-
+ > Another way to view the explain plan is by adding EXPLAIN PLAN FOR to
the front of your query, as follows:
+ >
+ >```sql
+ >EXPLAIN PLAN FOR
+ >SELECT
+ > "page",
+ > "countryName",
+ > COUNT(*) AS "Edits"
+ >FROM "wikipedia"
+ >WHERE "countryName" IS NOT NULL
+ >GROUP BY 1, 2
+ >ORDER BY "Edits" DESC
+ >```
+ >This is particularly useful when running queries
+ from the command line or over HTTP.
-The console query view provides autocomplete functionality with inline
documentation.
-
+9. Finally, click `...` and **Edit context** to see how you can add
additional parameters controlling the execution of the query execution. In the
field, enter query context options as JSON key-value pairs, as described in
[Context flags](../querying/query-context.md).
-You can also configure extra [context flags](../querying/query-context.md) to
be sent with the query from the `...` options menu.
+That's it! We've built a simple query using some of the query builder features
built into the Druid Console. The following
+sections provide a few more example queries you can try. Also, see [Other ways
to invoke SQL queries](#other-ways-to-invoke-sql-queries) to learn how
+to run Druid SQL from the command line or over HTTP.
-Note that the console will (by default) wrap your SQL queries in a limit where
appropriate so that queries such as `SELECT * FROM wikipedia` can complete.
-You can turn off this behavior from the `Smart query limit` toggle.
+## More Druid SQL examples
-
+Here is a collection of queries to try out:
+
+### Query over time
+
+```sql
+SELECT FLOOR(__time to HOUR) AS HourTime, SUM(sum_deleted) AS LinesDeleted
Review comment:
`sum_deleted` should be `deleted` here
##########
File path: docs/tutorials/tutorial-query.md
##########
@@ -24,56 +24,165 @@ sidebar_label: "Querying data"
-->
-This tutorial will demonstrate how to query data in Apache Druid, with
examples for Druid SQL and Druid's native query format.
+This tutorial demonstrates how to query data in Apache Druid using Druid SQL,
a SQL-like language
+for querying data in Druid.
-The tutorial assumes that you've already completed one of the 4 ingestion
tutorials, as we will be querying the sample Wikipedia edits data.
+It assumes that you've completed the [Quickstart](../tutorials/index.md)
+or one of the following tutorials, since we'll query datasources that you
would have created
+by following one of them:
* [Tutorial: Loading a file](../tutorials/tutorial-batch.md)
* [Tutorial: Loading stream data from Kafka](../tutorials/tutorial-kafka.md)
* [Tutorial: Loading a file using
Hadoop](../tutorials/tutorial-batch-hadoop.md)
-Druid queries are sent over HTTP.
-The Druid console includes a view to issue queries to Druid and nicely format
the results.
+There are various ways to run Druid SQL queries: from the Druid console, using
a command line utility
+and by posting the query by HTTP. We'll look at each of these.
-## Druid SQL queries
-Druid supports a dialect of SQL for querying.
+## Query SQL from the Druid console
-This query retrieves the 10 Wikipedia pages with the most page edits on
2015-09-12.
+The Druid console includes a view that makes it easier to build and test
queries, and
+view their results.
-```sql
-SELECT page, COUNT(*) AS Edits
-FROM wikipedia
-WHERE TIMESTAMP '2015-09-12 00:00:00' <= "__time" AND "__time" < TIMESTAMP
'2015-09-13 00:00:00'
-GROUP BY page
-ORDER BY Edits DESC
-LIMIT 10
-```
+1. Start up the Druid cluster, if it's not already running, and open the Druid
console in your web
+browser.
+
+2. Click **Query** from the header to open the Query view:
+
+ 
+
+ You can write queries directly in the edit pane, but we'll generate a
starter query
+ using query builder controls.
+
+3. Expand the wikipedia datasource tree in the left pane. We'll
+create a query for the page dimension.
+
+4. Click `page` and then **Show:page** from the menu:
+
+ 
+
+ A SELECT query appears in the query edit pane and immediately runs.
However, in this case, the query
+ returns no data, since by default the query filters for data from the last
day, while our data is considerably
+ older than that. Let's remove the filter.
+
+5. In the datasource tree, click `__time` and **Remove Filter**.
+
+ 
+
+6. Click **Run** to run the query.
+
+ You should now see two columns of data, a page name and the count:
+
+ 
+
+ Notice that the results are limited in the console to about a hundred, by
default, due to the **Smart query limit**
+ feature. This helps users avoid inadvertently running queries that return
an excessive amount of data, possibly
+ overwhelming their system.
+
+7. Let's edit the query directly and take a look at a few more query building
features in the editor.
+ Click in the query edit pane and make the following changes:
+
+ 1. Add a line after the first column, `"page"` and Start typing the name
of a new column, `"countryName"`. Notice that the autocomplete menu suggests
column names, functions, keywords, and more. Choose "countryName" and
+add the new column to the GROUP BY clause as well, either by name or by
reference to its position, `2`.
+
+ 2. For readability, replace `Count` column name with `Edits`, since the
`COUNT()` function actually
+returns the number of edits for the page. Make the same column name change in
the ORDER BY clause as well.
+
+ The `COUNT()` function is one of many functions available for use in
Druid SQL queries. You can mouse over a function name
+ in the autocomplete menu to see a brief description of a function. Also,
you can find more information in the Druid
+ documentation; for example, the `COUNT()` function is documented in
+ [Aggregation functions](../querying/sql.md#aggregation-functions).
+
+ The query should now be:
+
+ ```sql
+ SELECT
+ "page",
+ "countryName",
+ COUNT(*) AS "Edits"
+ FROM "wikipedia"
+ GROUP BY 1, 2
+ ORDER BY "Edits" DESC
+ ```
+
+ When you run the query again, notice that we're getting the new
dimension,`countryName`, but for most of the rows, its value
+ is null. Let's
+ show only rows with a `countryName` value.
+
+8. Click the countryName dimension in the left pane and choose the first
filtering option. It's not exactly what we want, but
+we'll edit it by hand. The new WHERE clause should appear in your query.
+
+8. Modify the WHERE clause to exclude results that do not have a value for
countryName:
+
+ ```sql
+ WHERE "countryName" IS NOT NULL
+ ```
+ Run the query again. You should now see the top edits by country:
+
+ 
-Let's look at the different ways to issue this query.
+9. Under the covers, every Druid SQL query is translated into a query in the
JSON-based _Druid native query_ format before it runs
+ on data nodes. You can view the native query for this query by clicking `...`
and **Explain SQL Query**.
-### Query SQL via the console
+ While you can use Druid SQL for most purposes, familiarity with native
query is useful for composing complex queries and for troubleshooting
+performance issues. For more information, see [Native
queries](../querying/querying.md).
-You can issue the above query from the console.
+ 
-
+ > Another way to view the explain plan is by adding EXPLAIN PLAN FOR to
the front of your query, as follows:
+ >
+ >```sql
+ >EXPLAIN PLAN FOR
+ >SELECT
+ > "page",
+ > "countryName",
+ > COUNT(*) AS "Edits"
+ >FROM "wikipedia"
+ >WHERE "countryName" IS NOT NULL
+ >GROUP BY 1, 2
+ >ORDER BY "Edits" DESC
+ >```
+ >This is particularly useful when running queries
+ from the command line or over HTTP.
-The console query view provides autocomplete functionality with inline
documentation.
-
+9. Finally, click `...` and **Edit context** to see how you can add
additional parameters controlling the execution of the query execution. In the
field, enter query context options as JSON key-value pairs, as described in
[Context flags](../querying/query-context.md).
-You can also configure extra [context flags](../querying/query-context.md) to
be sent with the query from the `...` options menu.
+That's it! We've built a simple query using some of the query builder features
built into the Druid Console. The following
+sections provide a few more example queries you can try. Also, see [Other ways
to invoke SQL queries](#other-ways-to-invoke-sql-queries) to learn how
+to run Druid SQL from the command line or over HTTP.
-Note that the console will (by default) wrap your SQL queries in a limit where
appropriate so that queries such as `SELECT * FROM wikipedia` can complete.
-You can turn off this behavior from the `Smart query limit` toggle.
+## More Druid SQL examples
-
+Here is a collection of queries to try out:
+
+### Query over time
+
+```sql
+SELECT FLOOR(__time to HOUR) AS HourTime, SUM(sum_deleted) AS LinesDeleted
+FROM wikipedia WHERE "__time" BETWEEN TIMESTAMP '2015-09-12 00:00:00' AND
TIMESTAMP '2015-09-13 00:00:00'
+GROUP BY 1
+```
+
+
+
+### General group by
+
+```sql
+SELECT channel, page, SUM(sum_added)
Review comment:
`sum_added` should be `added` here
##########
File path: docs/tutorials/tutorial-query.md
##########
@@ -24,56 +24,165 @@ sidebar_label: "Querying data"
-->
-This tutorial will demonstrate how to query data in Apache Druid, with
examples for Druid SQL and Druid's native query format.
+This tutorial demonstrates how to query data in Apache Druid using Druid SQL,
a SQL-like language
+for querying data in Druid.
-The tutorial assumes that you've already completed one of the 4 ingestion
tutorials, as we will be querying the sample Wikipedia edits data.
+It assumes that you've completed the [Quickstart](../tutorials/index.md)
+or one of the following tutorials, since we'll query datasources that you
would have created
+by following one of them:
* [Tutorial: Loading a file](../tutorials/tutorial-batch.md)
* [Tutorial: Loading stream data from Kafka](../tutorials/tutorial-kafka.md)
* [Tutorial: Loading a file using
Hadoop](../tutorials/tutorial-batch-hadoop.md)
-Druid queries are sent over HTTP.
-The Druid console includes a view to issue queries to Druid and nicely format
the results.
+There are various ways to run Druid SQL queries: from the Druid console, using
a command line utility
+and by posting the query by HTTP. We'll look at each of these.
-## Druid SQL queries
-Druid supports a dialect of SQL for querying.
+## Query SQL from the Druid console
-This query retrieves the 10 Wikipedia pages with the most page edits on
2015-09-12.
+The Druid console includes a view that makes it easier to build and test
queries, and
+view their results.
-```sql
-SELECT page, COUNT(*) AS Edits
-FROM wikipedia
-WHERE TIMESTAMP '2015-09-12 00:00:00' <= "__time" AND "__time" < TIMESTAMP
'2015-09-13 00:00:00'
-GROUP BY page
-ORDER BY Edits DESC
-LIMIT 10
-```
+1. Start up the Druid cluster, if it's not already running, and open the Druid
console in your web
+browser.
+
+2. Click **Query** from the header to open the Query view:
+
+ 
+
+ You can write queries directly in the edit pane, but we'll generate a
starter query
+ using query builder controls.
+
+3. Expand the wikipedia datasource tree in the left pane. We'll
+create a query for the page dimension.
+
+4. Click `page` and then **Show:page** from the menu:
+
+ 
+
+ A SELECT query appears in the query edit pane and immediately runs.
However, in this case, the query
+ returns no data, since by default the query filters for data from the last
day, while our data is considerably
+ older than that. Let's remove the filter.
+
+5. In the datasource tree, click `__time` and **Remove Filter**.
+
+ 
+
+6. Click **Run** to run the query.
+
+ You should now see two columns of data, a page name and the count:
+
+ 
+
+ Notice that the results are limited in the console to about a hundred, by
default, due to the **Smart query limit**
+ feature. This helps users avoid inadvertently running queries that return
an excessive amount of data, possibly
+ overwhelming their system.
+
+7. Let's edit the query directly and take a look at a few more query building
features in the editor.
+ Click in the query edit pane and make the following changes:
+
+ 1. Add a line after the first column, `"page"` and Start typing the name
of a new column, `"countryName"`. Notice that the autocomplete menu suggests
column names, functions, keywords, and more. Choose "countryName" and
+add the new column to the GROUP BY clause as well, either by name or by
reference to its position, `2`.
+
+ 2. For readability, replace `Count` column name with `Edits`, since the
`COUNT()` function actually
+returns the number of edits for the page. Make the same column name change in
the ORDER BY clause as well.
+
+ The `COUNT()` function is one of many functions available for use in
Druid SQL queries. You can mouse over a function name
+ in the autocomplete menu to see a brief description of a function. Also,
you can find more information in the Druid
+ documentation; for example, the `COUNT()` function is documented in
+ [Aggregation functions](../querying/sql.md#aggregation-functions).
+
+ The query should now be:
+
+ ```sql
+ SELECT
+ "page",
+ "countryName",
+ COUNT(*) AS "Edits"
+ FROM "wikipedia"
+ GROUP BY 1, 2
+ ORDER BY "Edits" DESC
+ ```
+
+ When you run the query again, notice that we're getting the new
dimension,`countryName`, but for most of the rows, its value
+ is null. Let's
+ show only rows with a `countryName` value.
+
+8. Click the countryName dimension in the left pane and choose the first
filtering option. It's not exactly what we want, but
+we'll edit it by hand. The new WHERE clause should appear in your query.
+
+8. Modify the WHERE clause to exclude results that do not have a value for
countryName:
+
+ ```sql
+ WHERE "countryName" IS NOT NULL
+ ```
+ Run the query again. You should now see the top edits by country:
+
+ 
-Let's look at the different ways to issue this query.
+9. Under the covers, every Druid SQL query is translated into a query in the
JSON-based _Druid native query_ format before it runs
+ on data nodes. You can view the native query for this query by clicking `...`
and **Explain SQL Query**.
-### Query SQL via the console
+ While you can use Druid SQL for most purposes, familiarity with native
query is useful for composing complex queries and for troubleshooting
+performance issues. For more information, see [Native
queries](../querying/querying.md).
-You can issue the above query from the console.
+ 
-
+ > Another way to view the explain plan is by adding EXPLAIN PLAN FOR to
the front of your query, as follows:
+ >
+ >```sql
+ >EXPLAIN PLAN FOR
+ >SELECT
+ > "page",
+ > "countryName",
+ > COUNT(*) AS "Edits"
+ >FROM "wikipedia"
+ >WHERE "countryName" IS NOT NULL
+ >GROUP BY 1, 2
+ >ORDER BY "Edits" DESC
+ >```
+ >This is particularly useful when running queries
+ from the command line or over HTTP.
-The console query view provides autocomplete functionality with inline
documentation.
-
+9. Finally, click `...` and **Edit context** to see how you can add
additional parameters controlling the execution of the query execution. In the
field, enter query context options as JSON key-value pairs, as described in
[Context flags](../querying/query-context.md).
-You can also configure extra [context flags](../querying/query-context.md) to
be sent with the query from the `...` options menu.
+That's it! We've built a simple query using some of the query builder features
built into the Druid Console. The following
+sections provide a few more example queries you can try. Also, see [Other ways
to invoke SQL queries](#other-ways-to-invoke-sql-queries) to learn how
+to run Druid SQL from the command line or over HTTP.
-Note that the console will (by default) wrap your SQL queries in a limit where
appropriate so that queries such as `SELECT * FROM wikipedia` can complete.
-You can turn off this behavior from the `Smart query limit` toggle.
+## More Druid SQL examples
-
+Here is a collection of queries to try out:
+
+### Query over time
+
+```sql
+SELECT FLOOR(__time to HOUR) AS HourTime, SUM(sum_deleted) AS LinesDeleted
+FROM wikipedia WHERE "__time" BETWEEN TIMESTAMP '2015-09-12 00:00:00' AND
TIMESTAMP '2015-09-13 00:00:00'
+GROUP BY 1
+```
+
+
+
+### General group by
+
+```sql
+SELECT channel, page, SUM(sum_added)
+FROM wikipedia WHERE "__time" BETWEEN TIMESTAMP '2015-09-12 00:00:00' AND
TIMESTAMP '2015-09-13 00:00:00'
+GROUP BY channel, page
+ORDER BY SUM(added) DESC
+```
-The query view provides contextual actions that can write and modify the query
for you.
+
Review comment:
`tutorial-query-04.png` should be updated to show the query above
##########
File path: docs/tutorials/tutorial-query.md
##########
@@ -24,56 +24,165 @@ sidebar_label: "Querying data"
-->
-This tutorial will demonstrate how to query data in Apache Druid, with
examples for Druid SQL and Druid's native query format.
+This tutorial demonstrates how to query data in Apache Druid using Druid SQL,
a SQL-like language
+for querying data in Druid.
-The tutorial assumes that you've already completed one of the 4 ingestion
tutorials, as we will be querying the sample Wikipedia edits data.
+It assumes that you've completed the [Quickstart](../tutorials/index.md)
+or one of the following tutorials, since we'll query datasources that you
would have created
+by following one of them:
* [Tutorial: Loading a file](../tutorials/tutorial-batch.md)
* [Tutorial: Loading stream data from Kafka](../tutorials/tutorial-kafka.md)
* [Tutorial: Loading a file using
Hadoop](../tutorials/tutorial-batch-hadoop.md)
-Druid queries are sent over HTTP.
-The Druid console includes a view to issue queries to Druid and nicely format
the results.
+There are various ways to run Druid SQL queries: from the Druid console, using
a command line utility
+and by posting the query by HTTP. We'll look at each of these.
-## Druid SQL queries
-Druid supports a dialect of SQL for querying.
+## Query SQL from the Druid console
-This query retrieves the 10 Wikipedia pages with the most page edits on
2015-09-12.
+The Druid console includes a view that makes it easier to build and test
queries, and
+view their results.
-```sql
-SELECT page, COUNT(*) AS Edits
-FROM wikipedia
-WHERE TIMESTAMP '2015-09-12 00:00:00' <= "__time" AND "__time" < TIMESTAMP
'2015-09-13 00:00:00'
-GROUP BY page
-ORDER BY Edits DESC
-LIMIT 10
-```
+1. Start up the Druid cluster, if it's not already running, and open the Druid
console in your web
+browser.
+
+2. Click **Query** from the header to open the Query view:
+
+ 
+
+ You can write queries directly in the edit pane, but we'll generate a
starter query
+ using query builder controls.
+
+3. Expand the wikipedia datasource tree in the left pane. We'll
+create a query for the page dimension.
+
+4. Click `page` and then **Show:page** from the menu:
+
+ 
+
+ A SELECT query appears in the query edit pane and immediately runs.
However, in this case, the query
+ returns no data, since by default the query filters for data from the last
day, while our data is considerably
+ older than that. Let's remove the filter.
+
+5. In the datasource tree, click `__time` and **Remove Filter**.
+
+ 
+
+6. Click **Run** to run the query.
+
+ You should now see two columns of data, a page name and the count:
+
+ 
+
+ Notice that the results are limited in the console to about a hundred, by
default, due to the **Smart query limit**
+ feature. This helps users avoid inadvertently running queries that return
an excessive amount of data, possibly
+ overwhelming their system.
+
+7. Let's edit the query directly and take a look at a few more query building
features in the editor.
+ Click in the query edit pane and make the following changes:
+
+ 1. Add a line after the first column, `"page"` and Start typing the name
of a new column, `"countryName"`. Notice that the autocomplete menu suggests
column names, functions, keywords, and more. Choose "countryName" and
+add the new column to the GROUP BY clause as well, either by name or by
reference to its position, `2`.
+
+ 2. For readability, replace `Count` column name with `Edits`, since the
`COUNT()` function actually
+returns the number of edits for the page. Make the same column name change in
the ORDER BY clause as well.
+
+ The `COUNT()` function is one of many functions available for use in
Druid SQL queries. You can mouse over a function name
+ in the autocomplete menu to see a brief description of a function. Also,
you can find more information in the Druid
+ documentation; for example, the `COUNT()` function is documented in
+ [Aggregation functions](../querying/sql.md#aggregation-functions).
+
+ The query should now be:
+
+ ```sql
+ SELECT
+ "page",
+ "countryName",
+ COUNT(*) AS "Edits"
+ FROM "wikipedia"
+ GROUP BY 1, 2
+ ORDER BY "Edits" DESC
+ ```
+
+ When you run the query again, notice that we're getting the new
dimension,`countryName`, but for most of the rows, its value
+ is null. Let's
+ show only rows with a `countryName` value.
+
+8. Click the countryName dimension in the left pane and choose the first
filtering option. It's not exactly what we want, but
+we'll edit it by hand. The new WHERE clause should appear in your query.
+
+8. Modify the WHERE clause to exclude results that do not have a value for
countryName:
+
+ ```sql
+ WHERE "countryName" IS NOT NULL
+ ```
+ Run the query again. You should now see the top edits by country:
+
+ 
-Let's look at the different ways to issue this query.
+9. Under the covers, every Druid SQL query is translated into a query in the
JSON-based _Druid native query_ format before it runs
+ on data nodes. You can view the native query for this query by clicking `...`
and **Explain SQL Query**.
-### Query SQL via the console
+ While you can use Druid SQL for most purposes, familiarity with native
query is useful for composing complex queries and for troubleshooting
+performance issues. For more information, see [Native
queries](../querying/querying.md).
-You can issue the above query from the console.
+ 
-
+ > Another way to view the explain plan is by adding EXPLAIN PLAN FOR to
the front of your query, as follows:
+ >
+ >```sql
+ >EXPLAIN PLAN FOR
+ >SELECT
+ > "page",
+ > "countryName",
+ > COUNT(*) AS "Edits"
+ >FROM "wikipedia"
+ >WHERE "countryName" IS NOT NULL
+ >GROUP BY 1, 2
+ >ORDER BY "Edits" DESC
+ >```
+ >This is particularly useful when running queries
+ from the command line or over HTTP.
-The console query view provides autocomplete functionality with inline
documentation.
-
+9. Finally, click `...` and **Edit context** to see how you can add
additional parameters controlling the execution of the query execution. In the
field, enter query context options as JSON key-value pairs, as described in
[Context flags](../querying/query-context.md).
-You can also configure extra [context flags](../querying/query-context.md) to
be sent with the query from the `...` options menu.
+That's it! We've built a simple query using some of the query builder features
built into the Druid Console. The following
+sections provide a few more example queries you can try. Also, see [Other ways
to invoke SQL queries](#other-ways-to-invoke-sql-queries) to learn how
+to run Druid SQL from the command line or over HTTP.
-Note that the console will (by default) wrap your SQL queries in a limit where
appropriate so that queries such as `SELECT * FROM wikipedia` can complete.
-You can turn off this behavior from the `Smart query limit` toggle.
+## More Druid SQL examples
-
+Here is a collection of queries to try out:
+
+### Query over time
+
+```sql
+SELECT FLOOR(__time to HOUR) AS HourTime, SUM(sum_deleted) AS LinesDeleted
+FROM wikipedia WHERE "__time" BETWEEN TIMESTAMP '2015-09-12 00:00:00' AND
TIMESTAMP '2015-09-13 00:00:00'
+GROUP BY 1
+```
+
+
Review comment:
`tutorial-query-03.png` should be updated to show the query above
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