Add link to SWC SQL lesson for further learning

Chris Erdmann · web-flow · commit b860b12441ba · 2019-06-21T17:03:24.000-04:00
diff --git a/_episodes/10-extra-challenges.md b/_episodes/10-extra-challenges.md
@@ -16,6 +16,8 @@ SQL queries help us *ask* specific *questions* which we want to answer about our
 
 Have a look at the following questions; these questions are written in plain English. Can you translate them to *SQL queries* and give a suitable answer?
 
+Also, if you would like to learn more SQL concepts and try additional challenges, see the [Software Carpentry Databases and SQL](https://swcarpentry.github.io/sql-novice-survey/) lesson.
+
 > ## Challenge 1
 > How many `articles` are there from each `First_author`? Can you make an alias for the number of articles? Can you order the results by articles?
 >

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`@@ -16,6 +16,8 @@ SQL queries help us ask specific questions which we want to answer about our`
`16`	`16`
`17`	`17`	`Have a look at the following questions; these questions are written in plain English. Can you translate them to SQL queries and give a suitable answer?`
`18`	`18`
	`19`	`+Also, if you would like to learn more SQL concepts and try additional challenges, see the [Software Carpentry Databases and SQL](https://swcarpentry.github.io/sql-novice-survey/) lesson.`
	`20`	`+`
`19`	`21`	`> ## Challenge 1`
`20`	`22`	> How many `articles` are there from each `First_author`? Can you make an alias for the number of articles? Can you order the results by articles?
`21`	`23`	`>`