ScalarDL TableStore SQL Grammar

This page provides a list of commands supported in ScalarDL TableStore SQL.

注記

ScalarDL TableStore SQL is a PartiQL-based language and is not fully compatible with standard SQL.

• DDL
  • CREATE TABLE
• DML
  • SELECT
  • INSERT
  • UPDATE
• Others
  • Show tables
  • Show record histories
• Literal
  • String
  • Number
  • Boolean

DDL

Data Definition Language (DDL) commands are used to define and modify the structure of database objects such as tables.

CREATE TABLE

The CREATE TABLE command creates a table.

Grammar

CREATE TABLE <table name> (
  <primary key column name> data_type PRIMARY KEY [, <index key column name> data_type,] ...
)

data_type: BOOLEAN | INT | BIGINT | FLOAT | DOUBLE PRECISION | STRING

Notes

• You don't have to specify a strict schema when creating a table, but you must specify a primary key column at least.
• You can create secondary indexes by specifying index key columns.
• ScalarDL TableStore handles all numeric data types (INT, BIGINT, FLOAT, and DOUBLE PRECISION) as the NUMBER data type in the JSON format without distinguishing them.

Examples

An example of CREATE TABLE is as follows:

-- Create a table with a primary key ("c1") and index keys ("c2", "c3", and "c4").
CREATE TABLE tbl (
  c1 INT PRIMARY KEY,
  c2 STRING,
  c3 FLOAT,
  c4 BIGINT
);

DML

Data Manipulation Language (DML) commands are used to query and modify data in tables.

SELECT

The SELECT command retrieves records in tables managed by TableStore.

Grammar

SELECT projection [, projection] ...
  FROM <table name> [AS <alias>] [join_specification [join_specification] ...]
  WHERE predicate [AND predicate ...]

projection: * | identifier
join_specification: JOIN <table name> [AS <alias>] ON join_predicate
join_predicate: identifier = identifier
predicate: identifier operator <literal> | identifier IS [NOT] NULL
identifier: [<table name>.]<column name> | [alias.]<column name>
operator: = | <> | != | > | >= | < | <=

Notes

• For the SELECT clause, you can specify top-level fields in the JSON record object as projection columns.
• For the JOIN clause, the join_predicates must include either a primary-key column or index-key column from the right table.
• For the WHERE clause, you can specify predicates for any columns, but you must include at least one predicate for a primary key column or index key column with the equality condition or IS NULL condition.

Examples

If you have the following table with the primary and index keys, for example:

CREATE TABLE tbl (
  c1 INT PRIMARY KEY,
  c2 STRING,
  c3 FLOAT,
  c4 BIGINT
);

Examples of SELECT are as follows:

-- With a primary key
SELECT * FROM tbl WHERE c1 = 10;

-- With a primary key and predicates for non-primary-key columns
SELECT * FROM tbl WHERE c1 = 10 AND c2 = 'aaa' AND c3 = 1.23 AND c4 < 100;

-- With projections and a primary key
SELECT c1, c2, c3, c5 FROM tbl WHERE c1 = 10;

-- With an equality predicate for an indexed column
SELECT * FROM tbl WHERE c4 = 100;

-- With an equality predicate for an indexed column and predicates for non-key columns
SELECT * FROM tbl WHERE c4 = 100 AND c5 = false;

-- With IS NULL predicates
SELECT * FROM tbl WHERE c2 IS NULL AND c3 IS NOT NULL;

-- With JOIN clause
SELECT * FROM tbl1 as t1 JOIN tbl2 as t2 on t1.c2=t2.id WHERE t1.c1=1;

INSERT

The INSERT command inserts a new record into the specified table. If the target record already exists, an exception will be thrown. In ScalarDL TableStore, a record is represented by a JSON object. You can also specify the JSON object by using the PartiQL struct format.

Grammar

INSERT INTO <table name> VALUES record_specification

record_specification: `<JSON object>` | <PartiQL struct>

Notes

You must include a primary key column in the record to be inserted.

Examples

Examples of INSERT are as follows:

-- Insert a record using the JSON format
INSERT INTO tbl VALUES `{"c1": 10, "c2": "aaa", "c3": 1.23, "c4": 100, "c5": true}`;

-- Insert a record using the PartiQL struct format
INSERT INTO tbl VALUES {'c1': 10, 'c2': 'aaa', 'c3': 1.23, 'c4': 100, 'c5': true};

UPDATE

The UPDATE command updates existing records in the specified table. You can specify conditions in the WHERE clause to filter records, the same as the SELECT command. Still, you must include at least one predicate for a primary key column or index key column with the equality condition or IS NULL condition.

Grammar

UPDATE <table name>
  SET <column name> = <literal> [, <column name> = <literal>] ...
  WHERE predicate [AND predicate ...]

predicate: <column name> operator <literal> | <column name> IS [NOT] NULL
operator: = | <> | != | > | >= | < | <=

Notes

• For the SET clause, if the specified column does not exist in the records, then it is newly added in the JSON object of the records.
• For the WHERE clause, you can specify predicates for any columns, but you must include at least one predicate for a primary key column or index key column with the equality condition or IS NULL condition.

Examples

If you have the following table, for example:

CREATE TABLE ns.tbl (
  c1 INT PRIMARY KEY,
  c2 STRING,
  c3 FLOAT,
  c4 BIGINT
);

Examples of UPDATE with the full primary key specified are as follows:

-- Update a record with a primary key predicate
UPDATE tbl SET c4 = 200, c5 = false WHERE c1 = 10;

-- Update a record with an index key predicate
UPDATE tbl SET c4 = 200, c5 = false WHERE c2 = 'aaa';

-- Update a record with a primary key and a non-key predicate
UPDATE tbl SET c4 = 200, c5 = false WHERE c1 = 10 AND c5 = true;

Others

Show tables

You can show tables managed by TableStore by querying the information_schema.tables table.

Grammar

SELECT *
  FROM information_schema.tables
  [WHERE table_name = <table name>]  

Examples

Examples of querying the information_schema.tables table are as follows:

-- Show all tables in tables managed by TableStore.
SELECT * FROM information_schema.tables;

-- Show only the specified table
SELECT * FROM information_schema.tables WHERE table_name = 'tbl';

Show record histories

You can show a history of the specified record by using the history() function.

Grammar

SELECT history()
  FROM <table name>
  WHERE predicate
  [LIMIT <limit>]

predicate: <column name> = <literal>

Notes

• You must specify a primary key in the WHERE clause.
• The command returns the records sorted from latest to oldest.
• With the LIMIT clause, the command returns the most recent <limit> rows sorted from latest to oldest.

Examples

Examples of showing a history of the specified record are as follows:

-- Show a history of the specified record
SELECT history() FROM tbl WHERE c1 = 10;

-- Show a history of the specified record with limit
SELECT history() FROM tbl WHERE c1 = 10 LIMIT 10;

Literal

Literal refers to a fixed data value used when writing SQL-like statements. For example, 1, 'abc', 1.23, and true are literals.

String

A string literal is a sequence of characters enclosed in single quotes ', such as 'abc' and 'abc def'.

Number

Number literals include exact-value (INTEGER and BIGINT) and approximate-value (FLOAT and DOUBLE PRECISION) literals:

• An exact-value literal is a sequence of digits, such as 123 and -5.
• An approximate-value literal is a sequence of digits with a decimal point, such as 4.754 and -1.2.

Boolean

Boolean literals are either true or false to represent boolean values.