支不支持 if exists()？ - V2EX

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This topic created in 2060 days ago, the information mentioned may be changed or developed.

像这样的，在 mysql 如何写？
IF EXISTS(SELECT * FROM shares WHERE file_id='1' AND user_id='4') THEN
SELECT * FROM shares WHERE file_id='1' AND user_id='4'
ELSE
SELECT * FROM shares WHERE file_id='2' AND user_id='5'
END IF

1 replies • 2021-02-07 11:50:08 +08:00

1

ElmerZhang

Feb 7, 2021

SELECT * FROM shares WHERE ( file_id='1' AND user_id='4' ) OR (file_id='2' AND user_id='5') ORDER BY file_id ASC LIMIT 1;

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