Hello Julie,

SQL Experience is not required to work with K2. The K2 Database should not be modified, so you shouldn't need to have any experience. K2 Support may ask to take a look at the DB if there is an issue that arises, but SQL experience on your side is not required. Now a minor knowledge of SQL will be beneficial for troubleshooting, but not required. 

K2 Smartobjects allow you to create your own tables similar to SharePoint lists. These SmartObjects behave just like SQL tables (they actually are SQL tables themselves) so this can be your stand in for SQL.

I recommend taking a look at the following tutorial:

https://www.w3schools.com/sql/

This site does a great job of starting you out simple and can help with more complex learning if you would like to delve into it. It also allows you to practice the SQL queries on the site itself, so you can see how everything would look in SQL. 

Thanks for the answer MT, that's good to hear, I'll take a look at the link provided too :-)

SQL Server: Almost all SharePoint data is stored here, but that should not intimidate you.

Honing your sql skills is resourceful to solving and keeping up-to-date with the advancement of these platforms.

Here are some basic queries to familiarise yourself with:

1. To get the total number of space utilized by all the SharePoint databases in SQL server:

SELECT CONVERT(DECIMAL(10,2),(SUM(size * 8.00) / 1024.00 / 1024.00)) As UsedSpace 

FROM master.sys.master_files 

2. To get the name of all the SharePoint databases in a SQL instance:

Select * from Sys.Databases 

3. To get the total number of space utilized by all the SharePoint databases in SQL server:

SELECT CONVERT(DECIMAL(10,2),(SUM(size * 8.00) / 1024.00 / 1024.00)) As UsedSpace 

FROM master.sys.master_files 

4. To find the size consumed by SharePoint Databases individually in SQL Server:

SELECT DB_NAME(database_id) AS DatabaseName, 

Name AS Logical_Name, 

Physical_Name, (size*8)/1024 SizeMB 

FROM sys.master_files 

To sharpen your sql skills you could focus on basic sql scripts and advance to the one's provided on the link below.

https://demantprasad.wordpress.com/category/useful-sql-queries-for-sharepoint-content-database/

I hope this input adds value to your question.

Note: Altering the K2 Database in any way will put you in an unsupported state. This means that only select queries are  permitted on a customer level. When any other changes must be made to the Database, A support ticket must be logged, and an SQL Script must be compiled by our labs team. See the examples below for queries permitted to be run on the K2 database.

SQL knowledge is not that important to use K2 and integrate with K2. SQL knowledge can merely indicate problems that can in turn show you when to log a support ticket for a script fix. May I suggest using our user guide by clicking on the links listed below to study K2 integration on our User Guide which will be more efficient time spent in the light of integration with K2.

Integration: https://help.k2.com/onlinehelp/k2five/userguide/5.2/default.htm#How-Tos/LandingPages/HowToIntegration.htm%3FTocPath%3DHow%2520Tos%7C_____4

Integration with other Systems: https://help.k2.com/onlinehelp/k2five/userguide/5.2/default.htm#ServiceBrokers/OtherSystems.htm%3FTocPath%3DCreate%7CSmartObjects%7CIntegrating%2520with%2520other%2520systems%7C_____0