Count Vs Exists (ARCH5063)

Key go.orm.count-vs-exists · Severity info · Category orm

Using count > 0 to test for row presence makes the DB count every matching row. Use an exists query that can stop at the first row instead.

Incorrect

var count int64
db.Model(&User{}).Where("email = ?", email).Count(&count)
if count > 0 {
    // present
}

Correct

var exists bool
db.Model(&User{}).
    Select("1").
    Where("email = ?", email).
    Limit(1).
    Find(&exists)
if exists {
    // present
}

Fix

For presence checks use a Limit(1) short-circuit query instead of Count, which scans all matching rows.