Kyle Brandt kylebrandt

SQL Expressions Go MySQL Fork Notes

Why a Fork?

For dolthub/go-mysql-server, MySQL compatibility is a top priority. For Grafana, avoiding Cgo is a top priority. dolthub/go-mysql-server uses Cgo for regex by default. You can disable it with a build tag, but then people have to know about that build tag for things like go test (and Mac users have issues with the dependency, we tried and go Makefile and CI working, but then realized we would still have this bump for devs).

So this is a minimal fork which makes non-cgo the default.

References

Have PR and Commit links in a table with GH datasource. Join two Github datasource queries, extracting the PR id from the commit message.

One could do things get labbels for commits this way to (the labels of the PR that the commit came from)

SELECT
  grafana_prs.title AS pr_title,

func TestWhereOnNullNumber(t *testing.T) {
	f := &data.Frame{
		RefID: "a",
		Name:  "a",
		Fields: []*data.Field{
			//data.NewField("d", nil, []*float64{p(2.35), p(math.NaN())}),
			data.NewField("d", nil, []float64{2.35, math.NaN()}),
		},
	}

SQL Expressions -- Errors, No Data and Dynamic Schema Query Responses

There are three general situations that SQL expressions does not handle gracefully that users should be aware of that are not bugs, but rather current limitations of the feature. Those are:

Error Responses
No Data Responses
Dynamic Schema responses (Ones where columns are labels change between executions of the query)

Why are there these limitations?

Dataplane FAQ

Note: much of this is moved to grafana/dataplane#56

How does dataplane relate to Dataframes?

Dataplane adds a data typing layer on top of data frames. By analogy Dataplane Types are to dataframes as typescript is to javascript.

Specifically, a property is added to the dataframe to indicate its type with is made up of a kind and a format, for example "Timeseries Wide".

The queries

Panel: Main Sheet

SQL:

SELECT title, author, copyright, href, image, rating, series
FROM main

Smooth Time Series (PromQL DS)

Trend line over Time Series (PromQL DS)

Aggregation and Math across Different Queries (Azure Metrics)

Calculate percentage of syn packages against total packets, per direction

	{
	"__inputs": [
	{
	"name": "DS_MOCK",
	"label": "Mock",
	"description": "",
	"type": "datasource",
	"pluginId": "grafana-mock-datasource",
	"pluginName": "Mock"
	},

	HTTP/1.1 200 OK
	Audit-Id: 5b82aaf1-4ba7-48bc-bb7b-94a7b89c6c5e
	Cache-Control: no-store
	Content-Type: application/json
	X-Content-Type-Options: nosniff
	X-Frame-Options: deny
	X-Xss-Protection: 1; mode=block
	Date: Fri, 19 Sep 2025 14:51:41 GMT
	Content-Length: 902
	Connection: close

	/* Long
	WITH movie_genre AS (
	SELECT
	A.title,
	A.year,
	B.Genre AS genre
	FROM A
	JOIN B ON A.imdb_id = B.imdb_id
	),
	genre_totals AS (