convert go-pg query into plain sql - go

Question

Is it possible to convert go-pg query
err = db.Model(story).
Relation("Author").
Where("story.id = ?", story1.Id).
Select()
into plain SQL?
It would be helpful for debugging. So I could copy this plain SQL query and run in psql client as a string.
Probably there is some kind of package for this?

Answer 1

This is listed in the project's wiki:
How to view queries this library generates?
How to view queries this library generates?
You can setup query logger like this:
type dbLogger struct { }
func (d dbLogger) BeforeQuery(c context.Context, q *pg.QueryEvent) (context.Context, error) {
return c, nil
}
func (d dbLogger) AfterQuery(c context.Context, q *pg.QueryEvent) (context.Context, error) {
fmt.Println(q.FormattedQuery())
return c, nil
}
db := pg.Connect(&pg.Options{...})
db.AddQueryHook(dbLogger{})

Answer 2

Problem: There is no default parsing to RAW sql from ORM since v10.
Well, that's too late i guess. Maybe someone (like me) will face this problem in 2021. There is some steps how you could solve this:
[x] Read DOCs.
[x] Check all structs.
[x] Implement all methods.
Solving the problem
This solve is "forked" from this issue but i'll explain it step by step.
First of all we need to read some source code of go-pg hook.
As I said before: we need to check all structs from this doc. But we're lucky. There is only 1 struct!
// QueryEvent ...
type QueryEvent struct {
StartTime time.Time
DB orm.DB
Model interface{}
Query interface{}
Params []interface{}
fmtedQuery []byte
Result Result
Err error
Stash map[interface{}]interface{}
}
We don't really need to implement this struct completely.
But when you use db.AddQueryHook() (where db is ref on our DB connection and AddQueryHook() is method) AddQueryHook() wait's from you this interface:
type QueryHook interface {
BeforeQuery(context.Context, *QueryEvent) (context.Context, error)
AfterQuery(context.Context, *QueryEvent) error
}
So, we already read DOCs, checked structs. And what's next? Answer is pretty easy:
Implement all methods.
TBH, I thought that this is harder than it is.
To implement it you just need to create 2 methods of current (new empty) structure that implements functionality of methods above, like this:
Creating empty structure
type dbLogger struct{}
Adding methods from doc:
func (d dbLogger) BeforeQuery(c context.Context, q *pg.QueryEvent) (context.Context, error) {
return c, nil
}
func (d dbLogger) AfterQuery(c context.Context, q *pg.QueryEvent) error {
fq, _ := q.FormattedQuery()
fmt.Println(string(fq))
return nil
}
I hope this helps everyone who ever encounters this problem.

Answer 3

I've just been upgrading from go-pg v7 to v10 & had a problem where Query.AppendFormat() which is what I was using to get the RAW SQL had been removed.
After using the comments in this post for inspiration I managed extract it, using the code below
import (
"github.com/go-pg/pg/v10/orm"
)
func QueryToString(q *orm.Query) string {
value, _ := q.AppendQuery(orm.NewFormatter(), nil)
return string(value)
}
Hope this helps future viewers

Answer 4

//db your *pg.DB
// q your *orm.Query = db.Model(&yourModel).
qq := pg.QueryEvent{
DB: db,
Model: q.TableModel(),
Query: q,
}
fmt.Println(qq.FormattedQuery())
So in your case
q:= db.Model(story).
Relation("Author").
Where("story.id = ?", story1.Id)
fmt.Println("running SQL:")
qq := pg.QueryEvent{
DB: db,
Model: q.TableModel(),
Query: q,
}
fmt.Println(qq.FormattedQuery())
q.Select()