codesnips

sql

ruby 
class OverdueInvoicesQuery
  def initialize(relation: Invoice.all, as_of: Time.current)
    @relation = relation
    @as_of = as_of
  end

ActiveRecord::Relation as a Boundary (No Arrays)

rails activerecord query-objects
by codesnips 3 tabs
sql 
-- Basic EXPLAIN
EXPLAIN
SELECT * FROM users WHERE email = 'alice@example.com';

-- EXPLAIN with cost and row estimates
-- Output shows: Seq Scan on users (cost=0.00..15.50 rows=1 width=100)

EXPLAIN and query plan optimization

sql explain query-optimization
by Maria Garcia 2 tabs
go 
package store

import (
  "context"

  sq "github.com/Masterminds/squirrel"

Safe dynamic SQL with squirrel (optional filters, stable ordering)

go sql postgres
by Leah Thompson 1 tab
sql 
CREATE TABLE subscriptions (
    id                  BIGGENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    customer_id         BIGINT       NOT NULL,
    plan_code           TEXT         NOT NULL,
    status              TEXT         NOT NULL DEFAULT 'active',
    current_period_end  TIMESTAMPTZ  NOT NULL,

Partial index for “active” rows in Postgres

postgres performance sql
by codesnips 3 tabs
go 
package store

import (
  "context"
  "time"

pgxpool initialization with max connections and statement timeout

go postgres pgx
by Leah Thompson 1 tab
ruby 
class ReportsController < ApplicationController
  def monthly_sales
    year = params.fetch(:year, Date.current.year).to_i
    rows = Order.monthly_sales(year: year)
    @report = MonthlySalesReport.new(rows, year: year)

Aggregate Monthly Sales Reports in Rails with group_by SQL and a Presenter

rails postgres reporting
by codesnips 3 tabs
ruby 
module KeysetPaginatable
  extend ActiveSupport::Concern

  class_methods do
    def keyset_page(cursor: nil, limit: 20, direction: :desc)
      limit = limit.to_i.clamp(1, 100)

Keyset Cursor Pagination for ActiveRecord Instead of OFFSET

ruby rails activerecord
by codesnips 4 tabs
go 
package feed

import (
	"encoding/base64"
	"encoding/json"
	"time"

Cursor-Based Keyset Pagination for a Postgres Feed API in Go

go postgres pagination
by codesnips 3 tabs
go 
package store

import (
  "context"
  "database/sql"
)

db/sql prepared statements with context and explicit Close

go sql postgres
by Leah Thompson 1 tab
sql 
-- ROLLUP for hierarchical subtotals
SELECT
  COALESCE(category, 'ALL CATEGORIES') AS category,
  COALESCE(subcategory, 'ALL SUBCATEGORIES') AS subcategory,
  SUM(revenue) AS total_revenue,
  COUNT(*) AS order_count

Advanced aggregation and analytical functions

sql aggregation analytics
by Maria Garcia 2 tabs
go 
package bank

import "errors"

var ErrVersionConflict = errors.New("optimistic lock: version conflict")
var ErrInsufficientFunds = errors.New("insufficient funds")

Optimistic Locking in Go With a Version Column on UPDATE

optimistic-locking concurrency postgres
by codesnips 3 tabs
sql 
CREATE TYPE outbox_status AS ENUM ('pending', 'retry', 'processing', 'done', 'dead');

CREATE TABLE outbox_events (
    id           BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    dedupe_key   TEXT        NOT NULL,
    topic        TEXT        NOT NULL,

Atomic “Read + Mark Processed” with UPDATE … RETURNING

postgres concurrency reliability
by codesnips 3 tabs