A Go Template-Based SQL Builder and Struct Mapper

go get -u github.com/go-sqlt/sqlt

sqlt uses Go’s template engine to create a flexible, powerful, and type-safe SQL builder and struct mapper.

Struct mapping is handled by the structscan package. The Scan function (== structscan.Scan[Dest]()) provides a fluent API for field-based value extraction and transformation.

Example

package main

import (
	"context"
	"database/sql"
	"fmt"
	"math/big"
	"net/url"
	"time"

	"github.com/go-sqlt/sqlt"
	_ "modernc.org/sqlite"
)

type Data struct {
	Int    int64
	String string
	Bool   bool
	Time   time.Time
	Big    *big.Int
	URL    *url.URL
	Slice  []string
	JSON   map[string]any
}

var query = sqlt.All[string, Data](sqlt.Parse(`
	SELECT
		100                                    {{ Scan.Int.To "Int" }}
		, NULL                                 {{ Scan.Nullable.String.To "String" }}
		, true                                 {{ Scan.Bool.To "Bool" }}
		, {{ . }}                              {{ (Scan.String.ParseTime DateOnly).To "Time" }}
		, '300'                                {{ Scan.Text.To "Big" }}
		, 'https://example.com/path?query=yes' {{ Scan.Binary.To "URL" }}
		, 'hello,world'                        {{ (Scan.String.Split ",").To "Slice" }}
		, '{"hello":"world"}'                  {{ Scan.JSON.To "JSON" }}
`))

func main() {
	db, err := sql.Open("sqlite", ":memory:")
	if err != nil {
		panic(err)
	}

	data, err := query.Exec(context.Background(), db, time.Now().Format(time.DateOnly))
	if err != nil {
		panic(err)
	}

	fmt.Println(data) // [{100  true 2025-07-22 00:00:00 +0000 UTC 300 https://example.com/path?query=yes [hello world] map[hello:world]}]
}