Function buildUniqueKeyRangeEndTwoColumnViaTemptable

go/sql/builder.go:684–749

(
	databaseName, tableName string,
	uniqueKeyColumns *ColumnList,
	rangeStartArgs, rangeEndArgs []interface{},
	chunkSize int64,
	startRangeComparisonSign ValueComparisonSign,
	hint string,
)

}

func buildUniqueKeyRangeEndTwoColumnViaTemptable(
	databaseName, tableName string,
	uniqueKeyColumns *ColumnList,
	rangeStartArgs, rangeEndArgs []interface{},
	chunkSize int64,
	startRangeComparisonSign ValueComparisonSign,
	hint string,
) (result string, explodedArgs []interface{}, err error) {
	m := newTwoColumnRangeMeta(uniqueKeyColumns)
	if len(rangeStartArgs) != 2 || len(rangeEndArgs) != 2 {
		return "", nil, fmt.Errorf("expected 2 range args in buildUniqueKeyRangeEndTwoColumnViaTemptable, got %d start and %d end", len(rangeStartArgs), len(rangeEndArgs))
	}
	col2StartOp := string(startRangeComparisonSign)
	selectClause := m.col1Name + ", " + m.col2Name
	fromClause := databaseName + "." + tableName
	partSuffix := fmt.Sprintf("order by %s limit %d", m.orderByAsc, chunkSize)

	if sameFirstColumnValue(rangeStartArgs, rangeEndArgs) {
		result = fmt.Sprintf(`
			select /* gh-ost %s.%s %s */ %s, %s
			from (
				select %s, %s
				from %s.%s
				where (%s = %s and %s %s %s and %s <= %s)
				order by %s
				limit %d
			) select_osc_chunk
			order by %s
			limit 1`,
			databaseName, tableName, hint, m.col1Name, m.col2Name,
			m.col1Name, m.col2Name,
			databaseName, tableName,
			m.col1Name, m.col1Val, m.col2Name, col2StartOp, m.col2Val, m.col2Name, m.col2Val,
			m.orderByAsc, chunkSize,
			m.orderByDesc,
		)
		explodedArgs = append(explodedArgs, rangeStartArgs[0], rangeStartArgs[1], rangeEndArgs[1])
		return result, explodedArgs, nil
	}

	part1, part2, part3, explodedArgs := buildTwoColumnUnionParts(
		selectClause, fromClause,
		m.col1Name, m.col2Name,
		m.col1Val, m.col2Val, m.col1Val, m.col2Val,
		col2StartOp, partSuffix,
		rangeStartArgs, rangeEndArgs,
	)

	result = fmt.Sprintf(`
		select /* gh-ost %s.%s %s */ %s, %s
		from (
			select %s, %s
			from (%s union all %s union all %s) t
			order by %s
			limit %d
		) select_osc_chunk
		order by %s
		limit 1`,