在如 SELECT
pluviometers.*,
lastDate,
lastValue,
firstDate,
firstValue,
rain =
CASE firstDate
WHEN NULL THEN 0
ELSE (lastValue - firstValue) / (lastDate - firstDate)
END
FROM pluviometers
LEFT JOIN (
SELECT
h.pluviometer_id AS pid,
MAX(h.date) AS lastDate,
h.value AS lastValue
FROM rains h
LEFT JOIN (
SELECT
h2.pluviometer_id AS pid2,
MIN(h2.date) AS firstDate,
h2.value AS firstValue
FROM rains h2
WHERE h2.date > ###### GIVEN DATE ######
GROUP BY pid2
ORDER BY pid2 ASC
) AS p2 ON pid2 = h.pluviometer_id
GROUP BY pid
ORDER BY pid ASC
) AS p ON pid = pluviometers.id
GROUP BY pluviometers.id
ORDER BY pluviometers.id ASC
之类的声明中，是否可以知道哪一行匹配？如果是这样，怎么办呢？你会如何在PHP中捕获它？
答案 0 :(得分：4)
使用Case/IF声明
SELECT *,
case when row1='val1' then 'row1' else 'row2' end as matched col
FROM tbl1
WHERE row1='val1' OR row2='val2'
Case语句可以替换为IF语句，如此
IF(row1='val1','row1','row2')