- Introduction
- Concepts
- Architecture
- Key Features
- Horizontal Scalability
- MySQL Compatible Syntax
- Replicate from and to MySQL
- Distributed Transactions with Strong Consistency
- Cloud Native Architecture
- Minimize ETL with HTAP
- Fault Tolerance & Recovery with Raft
- Automatic Rebalancing
- Deployment and Orchestration with Ansible, Kubernetes, Docker
- JSON Support
- Spark Integration
- Read Historical Data Without Restoring from Backup
- Fast Import and Restore of Data
- Hybrid of Column and Row Storage
- SQL Plan Management
- Open Source
- Online Schema Changes
- How-to
- Get Started
- Deploy
- Hardware Recommendations
- From Binary Tarball
- Orchestrated Deployment
- Geographic Redundancy
- Data Migration with Ansible
- Configure
- Secure
- Transport Layer Security (TLS)
- Generate Self-signed Certificates
- Monitor
- Migrate
- Maintain
- Common Ansible Operations
- Backup and Restore
- Use BR (recommended)
- Identify Abnormal Queries
- Scale
- Upgrade
- Troubleshoot
- Reference
- SQL
- MySQL Compatibility
- SQL Language Structure
- Attributes
- Data Types
- Functions and Operators
- Function and Operator Reference
- Type Conversion in Expression Evaluation
- Operators
- Control Flow Functions
- String Functions
- Numeric Functions and Operators
- Date and Time Functions
- Bit Functions and Operators
- Cast Functions and Operators
- Encryption and Compression Functions
- Information Functions
- JSON Functions
- Aggregate (GROUP BY) Functions
- Window Functions
- Miscellaneous Functions
- Precision Math
- List of Expressions for Pushdown
- SQL Statements
ADD COLUMN
ADD INDEX
ADMIN
ADMIN CANCEL DDL
ADMIN CHECKSUM TABLE
ADMIN CHECK [TABLE|INDEX]
ADMIN SHOW DDL [JOBS|QUERIES]
ALTER DATABASE
ALTER INSTANCE
ALTER TABLE
ALTER USER
ANALYZE TABLE
BEGIN
CHANGE COLUMN
COMMIT
CREATE DATABASE
CREATE INDEX
CREATE ROLE
CREATE TABLE LIKE
CREATE TABLE
CREATE USER
CREATE VIEW
DEALLOCATE
DELETE
DESC
DESCRIBE
DO
DROP COLUMN
DROP DATABASE
DROP INDEX
DROP ROLE
DROP TABLE
DROP USER
DROP VIEW
EXECUTE
EXPLAIN ANALYZE
EXPLAIN
FLUSH PRIVILEGES
FLUSH STATUS
FLUSH TABLES
GRANT <privileges>
GRANT <role>
INSERT
KILL [TIDB]
LOAD DATA
LOAD STATS
MODIFY COLUMN
PREPARE
RECOVER TABLE
RENAME INDEX
RENAME TABLE
REPLACE
REVOKE <privileges>
REVOKE <role>
ROLLBACK
SELECT
SET DEFAULT ROLE
SET [NAMES|CHARACTER SET]
SET PASSWORD
SET ROLE
SET TRANSACTION
SET [GLOBAL|SESSION] <variable>
SHOW ANALYZE STATUS
SHOW CHARACTER SET
SHOW COLLATION
SHOW [FULL] COLUMNS FROM
SHOW CREATE TABLE
SHOW CREATE USER
SHOW DATABASES
SHOW ENGINES
SHOW ERRORS
SHOW [FULL] FIELDS FROM
SHOW GRANTS
SHOW INDEXES [FROM|IN]
SHOW INDEX [FROM|IN]
SHOW KEYS [FROM|IN]
SHOW PRIVILEGES
SHOW [FULL] PROCESSSLIST
SHOW SCHEMAS
SHOW STATUS
SHOW [FULL] TABLES
SHOW TABLE REGIONS
SHOW TABLE STATUS
SHOW [GLOBAL|SESSION] VARIABLES
SHOW WARNINGS
SPLIT REGION
START TRANSACTION
TRACE
TRUNCATE
UPDATE
USE
- Constraints
- Generated Columns
- Partitioning
- Character Set
- SQL Mode
- Views
- Configuration
- Security
- Transactions
- System Databases
- Errors Codes
- Supported Client Drivers
- Garbage Collection (GC)
- Performance
- Overview
- Understanding the Query Execution Plan
- The Blocklist of Optimization Rules and Expression Pushdown
- Introduction to Statistics
- TopN and Limit Push Down
- Optimizer Hints
- Follower Read
- Check the TiDB Cluster Status Using SQL Statements
- Execution Plan Binding
- Statement Summary Table
- Tune TiKV
- Operating System Tuning
- Column Pruning
- Key Monitoring Metrics
- Alert Rules
- Best Practices
- TiSpark
- TiKV
- TiFlash
- TiDB Binlog
- Tools
- Overview
- Use Cases
- Download
- TiDB Operator
- Table Filter
- Backup & Restore (BR)
- Mydumper
- Syncer
- Loader
- Data Migration
- TiDB Lightning
- sync-diff-inspector
- PD Control
- PD Recover
- TiKV Control
- TiDB Control
- TiDB in Kubernetes
- FAQs
- Support
- Contribute
- Releases
- All Releases
- v3.1
- v3.0
- v2.1
- v2.0
- v1.0
- Glossary
Important
You are viewing the documentation of an older version of the TiDB database (TiDB v3.1).
It is recommended that you use the latest LTS version of the TiDB database.
String Functions
TiDB supports most of the string functions available in MySQL 5.7.
Supported functions
Name | Description |
---|---|
ASCII() | Return numeric value of left-most character |
BIN() | Return a string containing binary representation of a number |
BIT_LENGTH() | Return length of argument in bits |
CHAR() | Return the character for each integer passed |
CHAR_LENGTH() | Return number of characters in argument |
CHARACTER_LENGTH() | Synonym for CHAR_LENGTH() |
CONCAT() | Return concatenated string |
CONCAT_WS() | Return concatenate with separator |
ELT() | Return string at index number |
EXPORT_SET() | Return a string such that for every bit set in the value bits, you get an on string and for every unset bit, you get an off string |
FIELD() | Return the index (position) of the first argument in the subsequent arguments |
FIND_IN_SET() | Return the index position of the first argument within the second argument |
FORMAT() | Return a number formatted to specified number of decimal places |
FROM_BASE64() | Decode to a base-64 string and return result |
HEX() | Return a hexadecimal representation of a decimal or string value |
INSERT() | Insert a substring at the specified position up to the specified number of characters |
INSTR() | Return the index of the first occurrence of substring |
LCASE() | Synonym for LOWER() |
LEFT() | Return the leftmost number of characters as specified |
LENGTH() | Return the length of a string in bytes |
LIKE | Simple pattern matching |
LOCATE() | Return the position of the first occurrence of substring |
LOWER() | Return the argument in lowercase |
LPAD() | Return the string argument, left-padded with the specified string |
LTRIM() | Remove leading spaces |
MAKE_SET() | Return a set of comma-separated strings that have the corresponding bit in bits set |
MID() | Return a substring starting from the specified position |
NOT LIKE | Negation of simple pattern matching |
NOT REGEXP | Negation of REGEXP |
OCT() | Return a string containing octal representation of a number |
OCTET_LENGTH() | Synonym for LENGTH() |
ORD() | Return character code for leftmost character of the argument |
POSITION() | Synonym for LOCATE() |
QUOTE() | Escape the argument for use in an SQL statement |
REGEXP | Pattern matching using regular expressions |
REPEAT() | Repeat a string the specified number of times |
REPLACE() | Replace occurrences of a specified string |
REVERSE() | Reverse the characters in a string |
RIGHT() | Return the specified rightmost number of characters |
RLIKE | Synonym for REGEXP |
RPAD() | Append string the specified number of times |
RTRIM() | Remove trailing spaces |
SPACE() | Return a string of the specified number of spaces |
STRCMP() | Compare two strings |
SUBSTR() | Return the substring as specified |
SUBSTRING() | Return the substring as specified |
SUBSTRING_INDEX() | Return a substring from a string before the specified number of occurrences of the delimiter |
TO_BASE64() | Return the argument converted to a base-64 string |
TRIM() | Remove leading and trailing spaces |
UCASE() | Synonym for UPPER() |
UNHEX() | Return a string containing hex representation of a number |
UPPER() | Convert to uppercase |
Unsupported functions
LOAD_FILE()
MATCH
SOUNDEX()
SOUNDS LIKE
WEIGHT_STRING()
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