Handling Variable-Length Fields

Concepts covered: sqlStringBuilding

The last common intermediate pattern: formatting values as strings for export. Numbers with thousands separators, dates in specific formats, currency with locale-appropriate symbols. The TO_CHAR (or FORMAT) function is the workhorse; the locale parameters are the tuning knobs. Formatting numbers Formatting dates Date formatting is engine-specific in syntax but consistent in capability. ISO 8601 format (YYYY-MM-DD HH:MI:SS) is the default for exports. Locale-specific formats (DD/MM/YYYY for European, MM/DD/YYYY for US) need explicit format strings. State this when designing: 'ISO 8601 for machine-readable exports; locale-specific only for human-facing dashboards where the consumer's locale is known.' Currency and locale Currency formatting needs both the number format and a currency symbol.

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