这是我的表的摘录：
gid | datepose | pvc ---------+----------------+------------ 1 | 1961 | 01 2 | 1949 | 3 | 1990 | 02 1 | 1981 | 1 | | 03 1 | |
我想使用SELECT CASE填写PVC列，如下所示：
SELECT gid,CASE WHEN (pvc IS NULL OR pvc = '') AND datpose < 1980) THEN '01' WHEN (pvc IS NULL OR pvc = '') AND datpose >= 1980) THEN '02' WHEN (pvc IS NULL OR pvc = '') AND (datpose IS NULL OR datpose = 0) THEN '03' END AS pvc FROM my_table ;
结果是与源表相同的内容，没有发生任何事情，我在pg_log文件中没有收到错误信息。这可能是一个语法错误，或在WHEN子句中使用多个条件的问题？
感谢您的帮助和建议！
这种代码也许应该适合你
SELECT *,CASE WHEN (pvc IS NULL OR pvc = '') AND (datepose < 1980) THEN '01' WHEN (pvc IS NULL OR pvc = '') AND (datepose >= 1980) THEN '02' WHEN (pvc IS NULL OR pvc = '') AND (datepose IS NULL OR datepose = 0) THEN '03' ELSE '00' END AS modifiedpvc FROM my_table; gid | datepose | pvc | modifiedpvc -----+----------+-----+------------- 1 | 1961 | 01 | 00 2 | 1949 | | 01 3 | 1990 | 02 | 00 1 | 1981 | | 02 1 | | 03 | 00 1 | | | 03 (6 rows)
