Function buildCondenseDeltaSQL

delta/controller.go:654–697

(viewName string, appender *DeltaAppender)

}

func buildCondenseDeltaSQL(viewName string, appender *DeltaAppender) string {
	var (
		augmentedSchema = appender.Schema()
		pkList          = getPrimaryKeyList(appender.BaseSchema())
		builder         strings.Builder
	)
	builder.Grow(512)
	// Select the last complete row without aggregating into an unnamed struct.
	// DuckDB 1.5 cannot extract fields from LAST(ROW(...)) reliably.
	builder.WriteString("SELECT ")
	for i, col := range augmentedSchema {
		if i > 0 {
			builder.WriteString(", ")
		}
		builder.WriteString(catalog.QuoteIdentifierANSI(col.Name))
		if isTimestampType(col.Type) {
			builder.WriteString("::TIMESTAMP")
		}
		builder.WriteString(" AS ")
		builder.WriteString(catalog.QuoteIdentifierANSI(col.Name))
	}
	builder.WriteString(" FROM ")
	builder.WriteString(viewName)
	builder.WriteString(" QUALIFY ROW_NUMBER() OVER (PARTITION BY ")
	builder.WriteString(pkList)
	builder.WriteString(" ORDER BY txn_group, txn_seq, txn_stmt, action) = COUNT(*) OVER (PARTITION BY ")
	builder.WriteString(pkList)
	builder.WriteString(")")
	return builder.String()
}

func isTimestampType(t sql.Type) bool {
	if types.IsTimestampType(t) {
		return true
	}
	if pgt, ok := t.(pgtypes.PostgresType); ok {
		return pgt.PG.OID == pgtype.TimestampOID
	}
	return false
}