1.問題說明

項目有兩個不同的平臺分別使用 Greenplum 和 MySQL 數(shù)據(jù)庫，但是這兩個數(shù)據(jù)庫的函數(shù)是不相同的，所以需要維護兩套查詢 SQL。

2.根據(jù)周幾獲取數(shù)據(jù)

2.1 原始函數(shù)結(jié)果

MySQL獲取周幾的函數(shù)為date_format( date, '%w')結(jié)果是周一到周日為：1，2，3，4，5，6，0

-- MySQL數(shù)據(jù)庫 SELECT '周一' AS weekInfo, date_format( '2022-04-11 08:00:00', '%w') AS weekVal UNION ALL SELECT '周二' AS weekInfo, date_format( '2022-04-12 08:00:00', '%w') AS weekVal UNION ALL SELECT '周三' AS weekInfo, date_format( '2022-04-13 08:00:00', '%w') AS weekVal UNION ALL SELECT '周四' AS weekInfo, date_format( '2022-04-14 08:00:00', '%w') AS weekVal UNION ALL SELECT '周五' AS weekInfo, date_format( '2022-04-15 08:00:00', '%w') AS weekVal UNION ALL SELECT '周六' AS weekInfo, date_format( '2022-04-16 08:00:00', '%w') AS weekVal UNION ALL SELECT '周日' AS weekInfo, date_format( '2022-04-17 08:00:00', '%w') AS weekVal

Greenplum獲取周幾的函數(shù)為to_char( timestamp, 'd')結(jié)果是周一到周日為：2，3，4，5，6，1

-- Greenplum數(shù)據(jù)庫 SELECT '周一' AS weekInfo, to_char( to_timestamp( '2022-04-11 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS weekVal UNION ALL SELECT '周二' AS weekInfo, to_char( to_timestamp( '2022-04-12 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS weekVal UNION ALL SELECT '周三' AS weekInfo, to_char( to_timestamp( '2022-04-13 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS weekVal UNION ALL SELECT '周四' AS weekInfo, to_char( to_timestamp( '2022-04-14 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS weekVal UNION ALL SELECT '周五' AS weekInfo, to_char( to_timestamp( '2022-04-15 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS weekVal UNION ALL SELECT '周六' AS weekInfo, to_char( to_timestamp( '2022-04-16 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS weekVal UNION ALL SELECT '周日' AS weekInfo, to_char( to_timestamp( '2022-04-17 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS weekVal

2.2 實現(xiàn)函數(shù)結(jié)果一致

可以看到 MySQL 的函數(shù)獲取的結(jié)果是數(shù)值，將結(jié)果+1即可實現(xiàn)與 Greenplum 數(shù)據(jù)庫函數(shù)結(jié)果一致。

-- MySQL數(shù)據(jù)庫 SELECT '周一' AS weekInfo, date_format( '2022-04-11 08:00:00', '%w') +1 AS weekVal UNION ALL SELECT '周二' AS weekInfo, date_format( '2022-04-12 08:00:00', '%w') +1 AS weekVal UNION ALL SELECT '周三' AS weekInfo, date_format( '2022-04-13 08:00:00', '%w') +1 AS weekVal UNION ALL SELECT '周四' AS weekInfo, date_format( '2022-04-14 08:00:00', '%w') +1 AS weekVal UNION ALL SELECT '周五' AS weekInfo, date_format( '2022-04-15 08:00:00', '%w') +1 AS weekVal UNION ALL SELECT '周六' AS weekInfo, date_format( '2022-04-16 08:00:00', '%w') +1 AS weekVal UNION ALL SELECT '周日' AS weekInfo, date_format( '2022-04-17 08:00:00', '%w') +1 AS weekVal

Greenplum 的函數(shù)獲取的結(jié)果是字符，需要將結(jié)果轉(zhuǎn)換成數(shù)值再-1即可實現(xiàn)與 MySQL 數(shù)據(jù)庫函數(shù)結(jié)果一致。

-- Greenplum數(shù)據(jù)庫 SELECT '周一' AS weekInfo, cast( to_char( to_timestamp( '2022-04-11 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS int) -1 AS weekVal UNION ALL SELECT '周二' AS weekInfo, cast( to_char( to_timestamp( '2022-04-12 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS int) -1 AS weekVal UNION ALL SELECT '周三' AS weekInfo, cast( to_char( to_timestamp( '2022-04-13 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS int) -1 AS weekVal UNION ALL SELECT '周四' AS weekInfo, cast( to_char( to_timestamp( '2022-04-14 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS int) -1 AS weekVal UNION ALL SELECT '周五' AS weekInfo, cast( to_char( to_timestamp( '2022-04-15 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS int) -1 AS weekVal UNION ALL SELECT '周六' AS weekInfo, cast( to_char( to_timestamp( '2022-04-16 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS int) -1 AS weekVal UNION ALL SELECT '周日' AS weekInfo, cast( to_char( to_timestamp( '2022-04-17 08:00:00', 'YYYY-MM-DD hh24:mi:ss' ), 'd' ) AS int) -1 AS weekVal

兩種方式選擇一種即可。

總結(jié)

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