General syntax

This topic describes the general syntax of SQL statements, including the syntax of constants, character sets, data types, SQL properties, distributed properties, and storage properties.

Constants

• INT_VALUE: matches integer constants such as 123.

• DECIMAL_VALUE: matches fixed-point constants such as 123.456.

• STR_VALUE: matches string constants such as abc.

• NULL: matches null constants.

• STORAGE_SIZE: matches storage size constants. The default unit of integer values is bytes, and the unit of string values can be set to M or G. For example, the size can be 1024 or '500M'.

const_value:
      INT_VALUE
     DECIMAL_VALUE
     STR_VALUE
     NULL
     STORAGE_SIZE

STORAGE_SIZE:
      INT_VALUE
     'INT_VALUE[MG]'

Character sets

charset:
      default_charset
     column_charset

default_charset:
    [DEFAULT] {CHARSET  CHARACTER SET} [=] {UTF8  UTF8MB4  BINARY}

column_charset:
    {CHARSET  CHARACTER SET} {UTF8  UTF8MB4  BINARY}

Collations

collate:
      default_collate
     column_collate

default_collate:
    [DEFAULT] COLLATE [=] {UTF8MB4_GENERAL_CI  UTF8MB4_BIN  BINARY}

column_collate:
    COLLATE {UTF8MB4_GENERAL_CI  UTF8MB4_BIN  BINARY}

Data types

data_type:
      TINYINT[(precision)] [UNSIGNED] [ZEROFILL] 
     SMALLINT[(precision)] [UNSIGNED] [ZEROFILL] 
     MEDIUMINT[(precision)] [UNSIGNED] [ZEROFILL] 
     INT[(precision)] [UNSIGNED] [ZEROFILL] 
     INTEGER[(precision)] [UNSIGNED] [ZEROFILL] 
     BIGINT[(precision)] [UNSIGNED] [ZEROFILL] 
     FLOAT[(precision, scale)] [UNSIGNED] [ZEROFILL] 
     DOUBLE[(precision, scale)] [UNSIGNED] [ZEROFILL] 
     DECIMAL[(precision [, scale])] [UNSIGNED] [ZEROFILL] 
     NUMERIC[(precision [, scale])] [UNSIGNED] [ZEROFILL] 
     DATETIME[(scale)] 
     TIMESTAMP[(scale)] 
     DATE
     TIME[(scale)] 
     YEAR
     VARCHAR(length) column_charset column_collate
     VARBINARY(length)
     CHAR[(length)] column_charset column_collate
     BINARY[(length)]
     TINYTEXT column_charset column_collate
     TINYLOB
     TEXT[(length)] column_charset column_collate
     BLOB[(length)]
     MEDIUMTEXT column_charset column_collate
     MEDIUMBLOB
     LONGTEXT column_charset column_collate
     LONGBLOB

precision  scale  length:
    INT_VALUE

SQL properties

• Object name

  tenant_name  pool_name  unit_name  zone_name  region_name:
      STR_VALUE
  
  database_name  table_name  table_alias_name  column_name column_alias_name   partition_name  subpartition_name:
      STR_VALUE
  
  index_name  view_name  object_name  constraint_name  tablegroup_name:
      STR_VALUE
  
  outline_name  user_name:
      STR_VALUE
  
  table_factor:
      [[database_name].] table_name
  
  column_factor:
      [table_factor.] column_name
  

• Expression

  expression:
        const_value
       column_factor
       operator_expression
       function_expression
  

• Comment

  comment:
      COMMENT 'comment_text'
  
  comment_text:
      STR_VALUE
  

Distributed properties

• PRIMARY_ZONE: specifies the leader distribution policy for data.

  primary_zone:
  PRIMARY_ZONE [=] zone_name
  

• ZONE_LIST: specifies the resource distribution policy for a tenant.

  zone_list:
  ZONE_LIST [=] (zone_name [, zone_name ...])
  

• REPLICA_NUM: specifies the number of replicas of data.

  replica_num:
  REPLICA_NUM [=] INT_VALUE
  

• TABLEGROUP: specifies the leader distribution policy for multiple data replicas.

  tablegroup:
        default_tablegroup
       table_tablegroup
  
  default_tablegroup:
      DEFAULT TABLEGROUP [=] {tablegroup_name  NULL}
  
  table_tablegroup:
      TABLEGROUP [=] {tablegroup_name  NULL}
  

Storage properties

• BLOCK_SIZE: specifies the microblock size for object storage.

  block_size:
  BLOCK_SIZE [=] INT_VALUE
  

• COMPRESSION: specifies the compression algorithm for object storage.

  compression:
  COMPRESSION [=] {NONE  LZ4_1.0  LZ0_1.0  SNAPPY_1.0  ZLIB_1.0}
  

• PCTFREE: specifies the macroblock reservation percentage for object storage.

  pctfree:
  PCTFREE [=] INT_VALUE
  

• TABLET_SIZE: specifies the minimum tablet size of a single task in a parallel compaction.

  tablet_size:
  TABLET_SIZE [=] INT_VALUE