SQLITE批量UPDATE语句

Question

我想执行许多SQL UPDATE语句,如下所示:

UPDATE cityd SET time_zone='-7.000000' WHERE locId = 173567;
UPDATE cityd SET time_zone='-8.000000' WHERE locId = 173568;
UPDATE cityd SET time_zone='-6.000000' WHERE locId = 173569;
UPDATE cityd SET time_zone='-5.000000' WHERE locId = 173570;
UPDATE cityd SET time_zone='-6.000000' WHERE locId = 173571;

我想优化事务时间,所以我需要使用BEGIN TRANSACTION/COMMIT对.如何在SQLtite Manager中的SQL语法中编写它？

编辑:当我在SQLite管理器中使用标准语法时,我收到以下错误消息:"SQLiteManager:BEGIN TRANSACTION; [无法在事务中启动事务"

Answer 1

根据SQL Documention,有两种支持的语法CASE

CASE x WHEN w1 THEN r1 WHEN w2 THEN r2 ELSE r3 END

CASE WHEN x = w1 THEN r1 WHEN x = w2 THEN r2 ELSE r3 END

因此,您的多个UPDATE语句可以进一步简化为

UPDATE  cityd
SET     time_zone = CASE locId
                        WHEN 173567 THEN '-7.000000'
                        WHEN 173568 THEN '-8.000000'
                        WHEN 173569 THEN '-6.000000'
                        WHEN 173570 THEN '-5.000000'
                        WHEN 173571 THEN '-6.000000'
                    END
WHERE   locId IN (173567, 173568, 173569, 173570, 173571)

Answer 2

BEGIN TRANSACTION;
.....YOUR SQL Statements here

COMMIT;