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更新时间：2024-06-29 GMT+08:00
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ALGORITHM

MySQL扩展了对ALTER TABLE … ALGORITHM=INSTANT的支持：用户可以在表的任何位置即时添加列、即时删除列、添加列时评估行大小限制。

GaussDB(DWS)不支持此属性，并在迁移过程中被DSC删除。

输入示例

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ALTER TABLE runoob_alter_test ALGORITHM=DEFAULT;
ALTER TABLE runoob_alter_test ALGORITHM=INPLACE;
ALTER TABLE runoob_alter_test ALGORITHM=COPY;
ALTER TABLE runoob_alter_test ADD COLUMN COL_18 VARCHAR(64)  DEFAULT '00', ALGORITHM=INSTANT;
ALTER TABLE runoob_alter_test MODIFY COLUMN dataType7 BIGINT, ALGORITHM=COPY;
ALTER TABLE `runoob_alter_test` ALGORITHM=DEFAULT, ALGORITHM=INPLACE, ALGORITHM=COPY;
ALTER TABLE `runoob_alter_test` ADD COLUMN dataType11 INT, ALGORITHM=DEFAULT, ALGORITHM=INPLACE, ALGORITHM=COPY;
ALTER TABLE runoob_alter_test CHANGE COLUMN dataType11 dataType12 SMALLINT ,ALGORITHM=INPLACE, ALGORITHM=COPY;
ALTER TABLE runoob_alter_test ALGORITHM=INPLACE, ALGORITHM=COPY, DROP COLUMN dataType12;

输出示例

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ALTER TABLE
  "public"."runoob_alter_test"
ADD
  COLUMN "col_18" VARCHAR(256) DEFAULT '00';
ALTER TABLE
  "public"."runoob_alter_test" MODIFY "datatype7" BIGINT NULL DEFAULT NULL;
ALTER TABLE
  "public"."runoob_alter_test"
ADD
  COLUMN "datatype11" INTEGER;
ALTER TABLE
  "public"."runoob_alter_test" CHANGE COLUMN "datatype11" "datatype12" SMALLINT NULL DEFAULT NULL;
ALTER TABLE
  "public"."runoob_alter_test" DROP COLUMN "datatype12" RESTRICT;
DROP TABLE IF EXISTS "public"."runoob_alter_test";