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SQL function

Type conversion functions

This article introduces the syntax of type conversion functions supported by TLS and common usage scenarios.

Function list

tip

In SQL statements for TLS analysis, use single quotes ('') to enclose string values. Characters without quotes or those enclosed in double quotes ("") are treated as field names or column names. For example, 'time' indicates a string, while time or "time" refers to a field or column name.

Function name	Syntax	Description
CAST function	CAST(KEY AS type)	Convert the data type of KEY
TRY_CAST function	TRY_CAST(KEY AS type)	Convert the data type of KEY
TYPEOF function	TYPEOF(KEY)	Query the data type of KEY.

CAST function

The CAST function converts the data type of a KEY. If a value fails to convert its data type when using the CAST function, the system will terminate the entire query and analysis operation.

Function syntax

Syntax format

CAST(KEY AS type)

Parameters description

Parameter	Description
KEY	Field or expression, the value can be of any data type.
type	SQL data types. Options include bigint, varchar, double, boolean, timestamp, decimal, array, or map. For example, CAST(JSON_PARSE(KEY) AS array(varchar)). For the mapping between index data types and SQL data types, see Data Type Mapping.

Description of return values

The return value data type matches the type parameter.

Function example

Scenarios

The child_type field is of varchar type. Use the CAST function to convert the child_type field value to MAP(varchar, varchar) type.

tip

In this example, the index data type of the child_type field is text. If the index data type is json, running the following statement will result in an error.

Log example

Query and analysis statements

* | SELECT CAST(JSON_PARSE(child_type) AS MAP(varchar, varchar))

Query and analysis results

TRY_CAST function

The TRY_CAST function is used to convert the data type of a KEY. When converting data types using the TRY_CAST function, if the type conversion of a value fails, the system returns NULL and continues processing by skipping that value.

Function syntax

Syntax format

TRY_CAST(KEY AS type)

Parameters description

Parameter	Description
KEY	Field or expression; the value can be any data type.
type	SQL data types: supported values are bigint, varchar, double, boolean, timestamp, decimal, array, or map. For example, TRY_CAST(JSON_PARSE(KEY) AS array(varchar)). For details on the mapping between index data types and SQL data types, see Data Type Mapping.

Return value description

The return value data type is consistent with the type parameter.

Function examples

Scenarios

Convert the value of the ReqTime field to varchar and return this data type.

Query and analysis statements

* | SELECT ReqTime,TYPEOF(TRY_CAST(ReqTime AS varchar))

Query and analysis results

TYPEOF function

The TYPEOF function is used to query the data type of a KEY.

Function syntax

Syntax format

TYPEOF(KEY)

Parameters description

Parameter
Description
KEY
Log fields and expressions can hold values of any data type

Return value description

The return value is of varchar type.

Function example

Scenarios

View the data type of the Method field

Log example

Query and analysis statements

* | SELECT TYPEOF(Method)

Query and analysis results

Data type mapping

The correspondence between index data types and SQL data types is shown in the table below:

Index data type	SQL data type
long	bigint
text	varchar
double	double
json	varchar

Last updated: 2025.10.29 15:17:17

Parameter	Description
KEY	Log fields and expressions can hold values of any data type