Help Center/ GaussDB(DWS)/ Tool Guide/ DSC: SQL Syntax Migration Tool/ MySQL Syntax Migration/ Table (Optional)

Updated on 2023-04-03 GMT+08:00

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Table (Optional)

This section describes the migration syntax of MySQL tables (optional parameter). The migration syntax determines how the keywords and features are migrated. GaussDB(DWS) does not support table migration. Currently, all table migration methods are temporary.

AUTO_INCREMENT

In database application, unique numbers that increase automatically are needed to identify records. In MySQL, the AUTO_INCREMENT attribute of a data column can be used to automatically generate the numbers. When creating a table, you can use AUTO_INCREMENT=n to specify a start value. You can also use the ALTER TABLE TABLE_NAME AUTO_INCREMENT=n command to reset the start value. GaussDB(DWS) does not support this attribute, which will be converted to SERIAL and deleted by DSC during migration.

Input

CREATE TABLE `public`.`job_instance` (
  `job_sche_id` int(11) NOT NULL AUTO_INCREMENT,
  `task_name` varchar(100) NOT NULL DEFAULT '',
  PRIMARY KEY (`job_sche_id`)
) ENGINE=InnoDB AUTO_INCREMENT=219 DEFAULT CHARSET=utf8;

Output

CREATE TABLE "public"."job_instance"
(
  "job_sche_id" SERIAL NOT NULL,
  "task_name" VARCHAR(100) NOT NULL DEFAULT '',
  PRIMARY KEY ("job_sche_id")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("job_sche_id");

In addition, GaussDB(DWS) does not support table definition modification using the AUTO_INCREMENT attribute. DSC will delete this attribute during migration.

Input

CREATE TABLE IF NOT EXISTS `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` FLOAT(10,2),
    PRIMARY KEY(`dataType1`)
);

ALTER TABLE runoob_alter_test AUTO_INCREMENT 100;
ALTER TABLE runoob_alter_test AUTO_INCREMENT=100;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(10),
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

AVG_ROW_LENGTH

Input

CREATE TABLE `public`.`runoob_tbl_test`(
    `runoob_id` VARCHAR(30),
    `runoob_title` VARCHAR(100) NOT NULL,
    `runoob_author` VARCHAR(40) NOT NULL,
    `submission_date` VARCHAR(30)
)AVG_ROW_LENGTH=10000;

Output

CREATE TABLE "public"."runoob_tbl_test"
(
  "runoob_id" VARCHAR(30),
  "runoob_title" VARCHAR(100) NOT NULL,
  "runoob_author" VARCHAR(40) NOT NULL,
  "submission_date" VARCHAR(30)
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("runoob_id");

In addition, GaussDB(DWS) does not allow using the AUTO_INCREMENT attribute to modify tables. DSC will delete the attribute after migration.

Input

CREATE TABLE IF NOT EXISTS `public`.`runoob_alter_test`( 
    `dataType1` int NOT NULL AUTO_INCREMENT, 
    `dataType2` FLOAT(10,2), 
    PRIMARY KEY(`dataType1`) 
); 
 
ALTER TABLE runoob_alter_test AUTO_INCREMENT 100; 
ALTER TABLE runoob_alter_test AUTO_INCREMENT=100;

Output

CREATE TABLE "public"."runoob_alter_test" 
( 
  "datatype1" SERIAL NOT NULL, 
  "datatype2" FLOAT(10), 
  PRIMARY KEY ("datatype1") 
) 
  WITH ( ORIENTATION = ROW, COMPRESSION = NO ) 
  NOCOMPRESS 
  DISTRIBUTE BY HASH ("datatype1");

CHARSET

CHARSET specifies the default character set for a table. GaussDB(DWS) does not support table definition modification using this attribute. DSC will delete the keyword during migration.

Input

CREATE TABLE `public`.`runoob_tbl_test`(
    `runoob_id` VARCHAR(30),
    `runoob_title` VARCHAR(100) NOT NULL,
    `runoob_author` VARCHAR(40) NOT NULL,
    `submission_date` VARCHAR(30)
)DEFAULT CHARSET=utf8;

Output

CREATE TABLE "public"."runoob_tbl_test"
(
  "runoob_id" VARCHAR(30),
  "runoob_title" VARCHAR(100) NOT NULL,
  "runoob_author" VARCHAR(40) NOT NULL,
  "submission_date" VARCHAR(30)
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("runoob_id");

CHECKSUM

In MySQL, CHECKSUM maintains a live checksum for all rows. GaussDB(DWS) does not support table definition modification using this attribute. DSC will delete the keyword during migration.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` FLOAT(10,2),
    `dataType3` DOUBLE(20,8),
    PRIMARY KEY(`dataType1`)
) CHECKSUM=1;

ALTER TABLE runoob_alter_test CHECKSUM 0;
ALTER TABLE runoob_alter_test CHECKSUM=0;

ALTER TABLE runoob_alter_test CHECKSUM 1;
ALTER TABLE runoob_alter_test CHECKSUM=1;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(10),
  "datatype3" FLOAT(20),
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

COLLATE

In MySQL, COLLATE specifies a default database sorting rule. GaussDB(DWS) does not support table definition modification using this attribute. DSC will delete the keyword during migration.

Input

CREATE TABLE `public`.`runoob_tbl_test`(
    `runoob_id` VARCHAR(30),
    `runoob_title` VARCHAR(100) NOT NULL,
    `runoob_author` VARCHAR(40) NOT NULL,
    `submission_date` VARCHAR(30)
) COLLATE=utf8_general_ci;

ALTER TABLE `public`.`runoob_tbl_test` COLLATE=utf8mb4_bin;

Output

CREATE TABLE "public"."runoob_tbl_test"
(
  "runoob_id" VARCHAR(30),
  "runoob_title" VARCHAR(100) NOT NULL,
  "runoob_author" VARCHAR(40) NOT NULL,
  "submission_date" VARCHAR(30)
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("runoob_id");

COMMENT

In MySQL, COMMENT is a comment for a table. GaussDB(DWS) does not support table definition modification using this attribute. DSC will delete the attribute during migration.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` FLOAT(10,2),
    PRIMARY KEY(`dataType1`)
) comment='table comment'; 

ALTER TABLE `public`.`runoob_alter_test` COMMENT 'table comment after modification';

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(10),
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

CONNECTION

GaussDB(DWS) does not support table definition modification using this attribute. DSC will delete the attribute during migration.

In MySQL, the keyword CONNECTION is used as a referenced, external data source. Currently, DSC cannot completely migrate the feature of CONNECTION. So as a workaround, it simply deletes the keyword.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` DOUBLE(20,8),
    `dataType3` TEXT NOT NULL,
    `dataType4` YEAR NOT NULL DEFAULT '2018',
    PRIMARY KEY(`dataType1`)
);

ALTER TABLE runoob_alter_test CONNECTION 'hello';
ALTER TABLE runoob_alter_test CONNECTION='hello';

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(20),
  "datatype3" TEXT NOT NULL,
  "datatype4" VARCHAR(4) NOT NULL DEFAULT '2018',
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

DELAY_KEY_WRITE

DELAY_KEY_WRITE is valid only for MyISAM tables. It is used to delay updates until the table is closed. GaussDB(DWS) does not support table definition modification using this attribute. DSC will delete the attribute during migration.

Input

CREATE TABLE `public`.`runoob_tbl_test`(
    `runoob_id` VARCHAR(30),
    `runoob_title` VARCHAR(100) NOT NULL,
    `runoob_author` VARCHAR(40) NOT NULL,
    `submission_date` VARCHAR(30)
) ENGINE=MyISAM, DELAY_KEY_WRITE=0;

ALTER TABLE `public`.`runoob_tbl_test6` DELAY_KEY_WRITE=1;

Output

CREATE TABLE "public"."runoob_tbl_test"
(
  "runoob_id" VARCHAR(30),
  "runoob_title" VARCHAR(100) NOT NULL,
  "runoob_author" VARCHAR(40) NOT NULL,
  "submission_date" VARCHAR(30)
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("runoob_id");

ENGINE

In MySQL, ENGINE specifies the storage engine for a table. When the storage engine is ARCHIVE, BLACKHOLE, CSV, FEDERATED, INNODB, MYISAM, MEMORY, MRG_MYISAM, NDB, NDBCLUSTER, or PERFORMANCE_SCHEMA, this attribute can be migrated and will be deleted during the migration.

Input

CREATE TABLE `public`.`runoob_alter_test`(    
`dataType1` int NOT NULL,    
`dataType2` DOUBLE(20,8),        
PRIMARY KEY(`dataType1`)
)ENGINE=MYISAM;

## A.
ALTER TABLE runoob_alter_test ENGINE INNODB;
ALTER TABLE runoob_alter_test ENGINE=INNODB;

## B.
ALTER TABLE runoob_alter_test ENGINE MYISAM;
ALTER TABLE runoob_alter_test ENGINE=MYISAM;

## C.
ALTER TABLE runoob_alter_test ENGINE MEMORY;
ALTER TABLE runoob_alter_test ENGINE=MEMORY;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" INTEGER NOT NULL,
  "datatype2" FLOAT(20),
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

-- A.

-- B.

-- C.

INSERT_METHOD

INSERT_METHOD specifies the table into which the row should be inserted. Use a value of FIRST or LAST to have inserts go to the first or last table, or a value of NO to prevent inserts. DSC will delete this attribute during migration.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` DOUBLE(20,8),
    `dataType3` TEXT NOT NULL,
    PRIMARY KEY(`dataType1`)
) INSERT_METHOD=LAST;

ALTER TABLE runoob_alter_test INSERT_METHOD NO;
ALTER TABLE runoob_alter_test INSERT_METHOD=NO;
ALTER TABLE runoob_alter_test INSERT_METHOD FIRST;
ALTER TABLE runoob_alter_test INSERT_METHOD=FIRST;
ALTER TABLE runoob_alter_test INSERT_METHOD LAST;
ALTER TABLE runoob_alter_test INSERT_METHOD=LAST;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(20),
  "datatype3" TEXT NOT NULL,
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

KEY_BLOCK_SIZE

KEY_BLOCK_SIZE choices vary depending on the storage engine used for a table. For MyISAM tables, KEY_BLOCK_SIZE optionally specifies the size in bytes to be used for index key blocks. For InnoDB tables, KEY_BLOCK_SIZE specifies the page size in kilobytes to be used for compressed InnoDB tables. GaussDB(DWS) does not support this attribute, which will be deleted by DSC during migration.

Input

CREATE TABLE `public`.`runoob_tbl_test`(
    `runoob_id` VARCHAR(30),
    `runoob_title` VARCHAR(100) NOT NULL,
    `runoob_author` VARCHAR(40) NOT NULL,
    `submission_date` VARCHAR(30)
) ENGINE=MyISAM KEY_BLOCK_SIZE=8;

ALTER TABLE runoob_tbl_test ENGINE=InnoDB;
ALTER TABLE runoob_tbl_test KEY_BLOCK_SIZE=0;

Output

CREATE TABLE "public"."runoob_tbl_test"
(
  "runoob_id" VARCHAR(30),
  "runoob_title" VARCHAR(100) NOT NULL,
  "runoob_author" VARCHAR(40) NOT NULL,
  "submission_date" VARCHAR(30)
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("runoob_id");

MAX_ROWS

In MySQL, MAX_ROWS indicates the maximum number of rows that can be stored in a table. This attribute will be deleted during migration using DSC.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` DOUBLE(20,8),
    `dataType3` TEXT NOT NULL,
    PRIMARY KEY(`dataType1`)
);

ALTER TABLE runoob_alter_test MAX_ROWS 100000;
ALTER TABLE runoob_alter_test MAX_ROWS=100000;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(20),
  "datatype3" TEXT NOT NULL,
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

MIN_ROWS

MIN_ROWS indicates the minimum number of rows that can be stored in a table. This attribute will be deleted during migration using DSC.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` DOUBLE(20,8),
    `dataType3` TEXT NOT NULL,
    PRIMARY KEY(`dataType1`)
);
ALTER TABLE runoob_alter_test MIN_ROWS 10000;
ALTER TABLE runoob_alter_test MIN_ROWS=10000;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(20),
  "datatype3" TEXT NOT NULL,
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

PACK_KEYS

In MySQL, PACK_KEYS specifies the index compression mode in the MyISAM storage engine. GaussDB(DWS) does not support this attribute, which will be deleted by DSC during migration.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` DOUBLE(20,8),
    `dataType3` TEXT NOT NULL,
    PRIMARY KEY(`dataType1`)
) ENGINE=MyISAM PACK_KEYS=1;

##A
ALTER TABLE runoob_alter_test PACK_KEYS 0;
ALTER TABLE runoob_alter_test PACK_KEYS=0;

##B
ALTER TABLE runoob_alter_test PACK_KEYS 1;
ALTER TABLE runoob_alter_test PACK_KEYS=1;

##C
ALTER TABLE runoob_alter_test PACK_KEYS DEFAULT;
ALTER TABLE runoob_alter_test PACK_KEYS=DEFAULT;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(10),
  "datatype3" FLOAT(20),
  "datatype4" TEXT NOT NULL,
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

--A

--B

--C

PASSWORD

In MySQL, PASSWORD indicates the user password. GaussDB(DWS) does not support this attribute, which will be deleted by DSC during migration.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` DOUBLE(20,8),
    `dataType3` TEXT NOT NULL,
    PRIMARY KEY(`dataType1`)
);
ALTER TABLE runoob_alter_test PASSWORD 'HELLO';

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(20),
  "datatype3" TEXT NOT NULL,
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

ROW_FORMAT

ROW_FORMAT defines the physical format in which the rows are stored. Row format choices vary depending on the storage engine used for the table. If you specify a row format that is not supported by the storage engine that is used for the table, the table will be created using that storage engine's default row format. If ROW_FORMAT is set to DEFAULT, the value will be migrated to SET NOCOMPRESS. If ROW_FORMAT is set to COMPRESSED, the value will be migrated to SET COMPRESS. GaussDB(DWS) supports only the preceding two ROW_FORMAT values. If other values are used, they will be deleted by DSC.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` FLOAT(10,2),
    `dataType3` DOUBLE(20,8),
    `dataType4` TEXT NOT NULL,
    PRIMARY KEY(`dataType1`)
) ENGINE=InnoDB;

## A.
ALTER TABLE runoob_alter_test ROW_FORMAT DEFAULT;
ALTER TABLE runoob_alter_test ROW_FORMAT=DEFAULT;

## B.
ALTER TABLE runoob_alter_test ROW_FORMAT DYNAMIC;
ALTER TABLE runoob_alter_test ROW_FORMAT=DYNAMIC;

## C.
ALTER TABLE runoob_alter_test ROW_FORMAT COMPRESSED;
ALTER TABLE runoob_alter_test ROW_FORMAT=COMPRESSED;

## D.
ALTER TABLE runoob_alter_test ROW_FORMAT REDUNDANT;
ALTER TABLE runoob_alter_test ROW_FORMAT=REDUNDANT;

## E.
ALTER TABLE runoob_alter_test ROW_FORMAT COMPACT;
ALTER TABLE runoob_alter_test ROW_FORMAT=COMPACT;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(10),
  "datatype3" FLOAT(20),
  "datatype4" TEXT NOT NULL,
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

-- A.
ALTER TABLE "public"."runoob_alter_test" SET NOCOMPRESS;
ALTER TABLE "public"."runoob_alter_test" SET NOCOMPRESS;

-- B.

-- C.
ALTER TABLE "public"."runoob_alter_test" SET COMPRESS;
ALTER TABLE "public"."runoob_alter_test" SET COMPRESS;

-- D.

-- E.

STATS_AUTO_RECALC

STATS_AUTO_RECALC specifies whether to automatically recalculate persistent statistics for an InnoDB table. GaussDB(DWS) does not support this attribute, which will be deleted by DSC during migration.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `runoob_id` VARCHAR(30),
    `runoob_title` VARCHAR(100) NOT NULL,
    `runoob_author` VARCHAR(40) NOT NULL,
    `submission_date` VARCHAR(30)
) ENGINE=InnoDB, STATS_AUTO_RECALC=DEFAULT;

## A.
ALTER TABLE runoob_alter_test STATS_AUTO_RECALC DEFAULT;
ALTER TABLE runoob_alter_test STATS_AUTO_RECALC=DEFAULT;

## B.
ALTER TABLE runoob_alter_test STATS_AUTO_RECALC 0;
ALTER TABLE runoob_alter_test STATS_AUTO_RECALC=0;

## C.
ALTER TABLE runoob_alter_test STATS_AUTO_RECALC 1;
ALTER TABLE runoob_alter_test STATS_AUTO_RECALC=1;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "runoob_id" VARCHAR(30),
  "runoob_title" VARCHAR(100) NOT NULL,
  "runoob_author" VARCHAR(40) NOT NULL,
  "submission_date" VARCHAR(30)
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("runoob_id");

-- A.

-- B.

-- C.

STATS_PERSISTENT

In MySQL, STATS_PERSISTENT specifies whether to enable persistence statistics for an InnoDB table. The CREATE TABLE and ALTER TABLE statements can be used to enable persistence statistics. DSC will delete this attribute during migration.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` DOUBLE(20,8),
    `dataType3` TEXT NOT NULL,
    PRIMARY KEY(`dataType1`)
) ENGINE=InnoDB, STATS_PERSISTENT=0;

## A.
ALTER TABLE runoob_alter_test STATS_PERSISTENT DEFAULT;
ALTER TABLE runoob_alter_test STATS_PERSISTENT=DEFAULT;

## B.
ALTER TABLE runoob_alter_test STATS_PERSISTENT 0;
ALTER TABLE runoob_alter_test STATS_PERSISTENT=0;

## C.
ALTER TABLE runoob_alter_test STATS_PERSISTENT 1;
ALTER TABLE runoob_alter_test STATS_PERSISTENT=1;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(20),
  "datatype3" TEXT NOT NULL,
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

-- A.

-- B.

-- C.

STATS_SAMPLE_PAGES

STATS_SAMPLE_PAGES specifies the number of index pages to sample when cardinality and other statistics for an indexed column are estimated. DSC will delete this attribute during migration.

Input

CREATE TABLE `public`.`runoob_alter_test`(
    `dataType1` int NOT NULL AUTO_INCREMENT,
    `dataType2` DOUBLE(20,8),
    `dataType3` TEXT NOT NULL,
    PRIMARY KEY(`dataType1`)
) ENGINE=InnoDB,STATS_SAMPLE_PAGES=25;

ALTER TABLE runoob_alter_test STATS_SAMPLE_PAGES 100;
ALTER TABLE runoob_alter_test STATS_SAMPLE_PAGES=100;

Output

CREATE TABLE "public"."runoob_alter_test"
(
  "datatype1" SERIAL NOT NULL,
  "datatype2" FLOAT(20),
  "datatype3" TEXT NOT NULL,
  PRIMARY KEY ("datatype1")
)
  WITH ( ORIENTATION = ROW, COMPRESSION = NO )
  NOCOMPRESS
  DISTRIBUTE BY HASH ("datatype1");

UNION

UNION is a table creation parameter of the MERGE storage engine. Creating a table using this keyword is similar to creating a common view. The created table logically combines the data of multiple tables that are specified by UNION. DSC migrates this feature to the view creation statement in GaussDB.

Input

CREATE TABLE t1 (
    a INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    message CHAR(20)
) ENGINE=MyISAM;

CREATE TABLE t2 (
    a INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    message CHAR(20)
) ENGINE=MyISAM;

CREATE TABLE total (
    a INT NOT NULL AUTO_INCREMENT,
    message CHAR(20))
ENGINE=MERGE UNION=(t1,t2) INSERT_METHOD=LAST;

Output

CREATE TABLE t1 (
    a SERIAL NOT NULL PRIMARY KEY,
    message CHAR(20)
)
WITH ( ORIENTATION = ROW, COMPRESSION = NO )
NOCOMPRESS
DISTRIBUTE BY HASH ("a");

CREATE TABLE t2 (
    a SERIAL NOT NULL PRIMARY KEY,
    message CHAR(20)
)
WITH ( ORIENTATION = ROW, COMPRESSION = NO )
NOCOMPRESS
DISTRIBUTE BY HASH ("a");

CREATE VIEW total(a, message) AS
SELECT * FROM t1
UNION ALL
SELECT * FROM t2;

Parent topic: MySQL Syntax Migration

Previous topic: Basic Data Types

Next topic: Table Operations

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Table (Optional)

AUTO_INCREMENT

AVG_ROW_LENGTH

CHARSET

CHECKSUM

COLLATE

COMMENT

CONNECTION

DELAY_KEY_WRITE

DIRECTORY

ENGINE

INSERT_METHOD

KEY_BLOCK_SIZE

MAX_ROWS

MIN_ROWS

PACK_KEYS

PASSWORD

ROW_FORMAT

STATS_AUTO_RECALC

STATS_PERSISTENT

STATS_SAMPLE_PAGES

UNION

Feedback

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