SQL Recipes vs PreGrade Ultra

An everyday SQL reference, from your first SELECT to window functions. Every query comes with an explanation, and most of them run. • 39 sections: filtering, sorting, calculated fields, functions, GROUP BY, window functions, subqueries, JOIN, UNION, INSERT and UPDATE, data types, tables, views. • Run in the app: more than half of the queries execute against a live practice database, and the result table appears below the query. Needs an internet connection. • Changes in new versions: 7 sections from SQL-92 to SQL:2023, showing what each standard added, with the old and the new query side by side. • Dialects compared: MySQL, PostgreSQL, SQLite, MS SQL Server, Oracle, Firebird, Access. Where they differ, each one is shown separately. • The practice database is the classic MySQL world sample database: countries, cities, languages. The tables are described in the app. • Edit any query and run it again; one tap brings the original back. • Add your own queries; they stay in the app and are always at hand. • Search by section name or by a fragment of a query. • Everything except running works offline. No account needed. WHAT THE FREE VERSION INCLUDES 12 runs and 12 edits a day; the limit resets every morning. The keyword reference is unlocked, with no limits. Up to 5 queries of your own. The full version unlocks every section, lifts the daily limits and raises the run limit to 80 a day. One purchase, no subscription. Built by a developer for developers. In active development since 2015.

PreGrade Ultra uses perspective correction to reduce the impact of camera angle on your centering measurements. **PERSPECTIVE CORRECTION** Other centering apps measure your photo as-is. If your camera is even slightly angled, your measurements can lose accuracy. PreGrade Ultra uses homography-based perspective correction to mathematically flatten your card to its true 63×88mm dimensions before measuring borders — centering analysis powered by computer vision. **PRECISION CENTERING ANALYSIS** - Measure left/right and top/bottom centering ratios - Millimeter-level border measurements - Front and back analysis with separate thresholds - Visual edge detection confirms your guide placement - Detect clockwise and counterclockwise print tilt **7 GRADING COMPANIES** Centering grades from PSA, BGS, CGC, TAG, SGC, ACE, and AGS. Every company has different thresholds — see which grade your card may qualify for at each one, with full threshold breakdowns. **CROSS-GRADE OPPORTUNITIES** Already have a graded card? See which companies may give a higher centering grade. The Understand tab highlights your potential best market-value grade at a glance. **MARKET PRICING** Look up active eBay listings for any Pokémon card. See current asking prices for raw and graded cards across most major grading companies. **BUILT FOR COLLECTORS, NOT ADVERTISERS** No ads. No banner spam. PreGrade Ultra is a tool built by a collector, for collectors. 3 free grading sessions included. Unlock unlimited access with a one-time Pro upgrade. **IMPORTANT:** PreGrade Ultra measures centering only. Card grading involves surface condition, corners, edges, and print quality — factors that cannot be assessed from a photo. Results are estimates and are not guaranteed to match any grading company's official assessment. PreGrade Ultra is not affiliated with, endorsed by, or sponsored by any grading company. Pokémon is a trademark of Nintendo, Creatures Inc., and GAME FREAK Inc. eBay is a trademark of eBay Inc. All company names and grading scales are trademarks of their respective owners.