如何使用 exists 关键字验证两个表中是否存在匹配值
为了查询两个表中是否存在匹配值，可以使用 exists 关键字。语法如下：
select *
from table1
where exists (
select *
from table2
where table1.column_name = table2.column_name
);根据你的问题，你希望检查主表中是否存在子表中的内容。你可以通过使用 exists 来验证这一点：
SELECT *
FROM (
SELECT pn_Code, serialNumber
FROM pnassertbasic_ruku pr
LEFT JOIN pnassertruku pu ON pr.parent_pnAssertRuku_id = pu.child_pnAssertRukuDetails_id
WHERE pn_Code IS NOT NULL AND serialNumber IS NOT NULL AND DATE(pr.create_time) = CURDATE() AND pr.warehouseEntryNumber <> 'WEd3791f0b'
) AS temp1
WHERE EXISTS (
SELECT *
FROM (
SELECT pn_Code, serialNumber
FROM pnassertbasic_ruku pr
LEFT JOIN pnassertruku pu ON pr.parent_pnAssertRuku_id = pu.child_pnAssertRukuDetails_id
WHERE pu.child_pnAssertRukuDetails_id IS NULL AND pr.warehouseEntryNumber = 'WEd3791f0b'
) AS temp2
WHERE temp1.pn_Code = temp2.pn_Code AND temp1.serialNumber = temp2.serialNumber
);已更正了拼写错误的 select，并调整了查询条件。
