WITH entry_date AS (
SELECT DATE '2018-04-03' AS start_date FROM dual
)
SELECT
start_date + (LEVEL - 1) * INTERVAL '1' YEAR AS period_start,
LEAST(start_date + LEVEL * INTERVAL '1' YEAR - INTERVAL '1' DAY, CURRENT_DATE) AS period_end
FROM
entry_date
CONNECT BY
start_date + (LEVEL - 1) * INTERVAL '1' YEAR <= CURRENT_DATE;
这样子？

首先，我们需要计算员工的入职日期和当前日期之间的年份差。然后，根据年份差生成时段序列。

以下是SQL查询：

WITH years_diff AS (
SELECT TRUNC(MONTHS_BETWEEN(SYSDATE, TO_DATE('2018-04-03', 'YYYY-MM-DD')) / 12) + 1 AS years
FROM DUAL
),
date_series AS (
SELECT LEVEL - 1 AS year_diff,
TO_DATE('2018-04-03', 'YYYY-MM-DD') + INTERVAL '1' YEAR * (LEVEL - 1) AS start_date,
TO_DATE('2018-04-03', 'YYYY-MM-DD') + INTERVAL '1' YEAR * LEVEL - INTERVAL '1' DAY AS end_date
FROM DUAL
CONNECT BY LEVEL <= (SELECT years FROM years_diff)
)
SELECT start_date, end_date
FROM date_series;

这个查询首先计算员工入职日期和当前日期之间的年份差（years_diff），然后使用CONNECT BY子句生成时段序列（date_series）。最后，从date_series中选择start_date和end_date。