Rechercher dans le manuel MySQL
Chapter 12 Functions and Operators
Table of Contents [+/-]
- 12.1 Function and Operator Reference
- 12.2 Type Conversion in Expression Evaluation
- 12.3 Operators [+/-]
- 12.4 Control Flow Functions
- 12.5 String Functions and Operators [+/-]
- 12.6 Numeric Functions and Operators [+/-]
- 12.7 Date and Time Functions
- 12.8 What Calendar Is Used By MySQL?
- 12.9 Full-Text Search Functions [+/-]
- 12.9.1 Natural Language Full-Text Searches
- 12.9.2 Boolean Full-Text Searches
- 12.9.3 Full-Text Searches with Query Expansion
- 12.9.4 Full-Text Stopwords
- 12.9.5 Full-Text Restrictions
- 12.9.6 Fine-Tuning MySQL Full-Text Search
- 12.9.7 Adding a Collation for Full-Text Indexing
- 12.9.8 ngram Full-Text Parser
- 12.9.9 MeCab Full-Text Parser Plugin
- 12.10 Cast Functions and Operators
- 12.11 XML Functions
- 12.12 Bit Functions and Operators
- 12.13 Encryption and Compression Functions
- 12.14 Locking Functions
- 12.15 Information Functions
- 12.16 Spatial Analysis Functions [+/-]
- 12.16.1 Spatial Function Reference
- 12.16.2 Argument Handling by Spatial Functions
- 12.16.3 Functions That Create Geometry Values from WKT Values
- 12.16.4 Functions That Create Geometry Values from WKB Values
- 12.16.5 MySQL-Specific Functions That Create Geometry Values
- 12.16.6 Geometry Format Conversion Functions
- 12.16.7 Geometry Property Functions
- 12.16.8 Spatial Operator Functions
- 12.16.9 Functions That Test Spatial Relations Between Geometry Objects
- 12.16.10 Spatial Geohash Functions
- 12.16.11 Spatial GeoJSON Functions
- 12.16.12 Spatial Convenience Functions
- 12.17 JSON Functions [+/-]
- 12.17.1 JSON Function Reference
- 12.17.2 Functions That Create JSON Values
- 12.17.3 Functions That Search JSON Values
- 12.17.4 Functions That Modify JSON Values
- 12.17.5 Functions That Return JSON Value Attributes
- 12.17.6 JSON Table Functions
- 12.17.7 JSON Schema Validation Functions
- 12.17.8 JSON Utility Functions
- 12.18 Functions Used with Global Transaction Identifiers (GTIDs)
- 12.19 MySQL Enterprise Encryption Functions [+/-]
- 12.20 Aggregate (GROUP BY) Functions [+/-]
- 12.21 Window Functions [+/-]
- 12.22 Performance Schema Functions
- 12.23 Internal Functions
- 12.24 Miscellaneous Functions
- 12.25 Precision Math [+/-]
Expressions can be used at several points in
SQL statements, such as in the
ORDER BY or HAVING clauses of
SELECT statements, in the
WHERE clause of a
SELECT,
DELETE, or
UPDATE statement, or in
SET
statements. Expressions can be written using literal values, column
values, NULL, built-in functions, stored
functions, user-defined functions, and operators. This chapter
describes the functions and operators that are permitted for writing
expressions in MySQL. Instructions for writing stored functions and
user-defined functions are given in
Section 24.2, “Using Stored Routines”, and
Section 29.4, “Adding New Functions to MySQL”. See
Section 9.2.4, “Function Name Parsing and Resolution”, for the rules describing how
the server interprets references to different kinds of functions.
An expression that contains NULL always produces
a NULL value unless otherwise indicated in the
documentation for a particular function or operator.
By default, there must be no whitespace between a function name and the parenthesis following it. This helps the MySQL parser distinguish between function calls and references to tables or columns that happen to have the same name as a function. However, spaces around function arguments are permitted.
You can tell the MySQL server to accept spaces after function names
by starting it with the
--sql-mode=IGNORE_SPACE option. (See
Section 5.1.11, “Server SQL Modes”.) Individual client programs can request
this behavior by using the CLIENT_IGNORE_SPACE
option for mysql_real_connect(). In
either case, all function names become reserved words.
For the sake of brevity, most examples in this chapter display the output from the mysql program in abbreviated form. Rather than showing examples in this format:
- +-----------+
- +-----------+
- | 2 |
- +-----------+
This format is used instead:
Document created the 26/06/2006, last modified the 26/10/2018
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