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# SQL As Understood By SQLite

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## Core Functions

The core functions shown below are available by default. Date & Time functions and aggregate functions are documented separately. An application may define additional functions written in C and added to the database engine using the sqlite3_create_function() API.

abs(X) | The abs(X) function returns the absolute value of the numeric argument X. Abs(X) returns NULL if X is NULL. Abs(X) return 0.0 if X is a string or blob that cannot be converted to a numeric value. If X is the integer -9223372036854775807 then abs(X) throws an integer overflow error since there is no equivalent positive 64-bit two complement value.
changes() | The changes() function returns the number of database rows that were changed or inserted or deleted by the most recently completed SQL statement. The changes() SQL function is a wrapper around the sqlite3_changes() C/C++ function and hence follows the same rules for counting changes.
coalesce(X,Y,...) | The coalesce() function returns a copy of its first non-NULL argument, or NULL if all arguments are NULL. Coalesce() must be at least 2 arguments.
glob(X,Y) | The glob(X,Y) function is equivalent to the expression "Y GLOB X". Note that the X and Y arguments are reversed in the glob() function relative to the infix GLOB operator. If the sqlite3_create_function() interface is used to override the glob(X,Y) function with an alternative implementation then the GLOB operator will invoke the alternative implementation.
ifnull(X,Y) | The ifnull() function returns a copy of its first non-NULL argument, or NULL if both arguments are NULL. Ifnull() must have exactly 2 arguments. The ifnull() function is equivalent to coalesce() with two arguments.
hex(X) | The hex() function interprets its argument as a BLOB and returns a string which is the upper-case hexadecimal rendering of the content of that blob.
last_insert_rowid() | The last_insert_rowid() function returns the ROWID of the last row insert from the database connection which invoked the function. The last_insert_rowid() SQL function is a wrapper around the sqlite3_last_insert_rowid() C/C++ interface function.
length(X) | The length(X) function returns the length of X in characters if X is a string, or in bytes if X is a blob. If X is NULL then length(X) is NULL. If X is numeric then length(X) returns the length of a string representation of X.
like(X,Y) like(X,Y,Z) | The like() function is used to implement the "Y LIKE X [ESCAPE Z]" expression. If the optional ESCAPE clause is present, then the like() function is invoked with three arguments. Otherwise, it is invoked with two arguments only. Note that the X and Y parameters are reversed in the like() function relative to the infix LIKE operator. The sqlite3_create_function() interface can be used to override the like() function and thereby change the operation of the LIKE operator. When overriding the like() function, it may be important to override both the two and three argument versions of the like() function. Otherwise, different code may be called to implement the LIKE operator depending on whether or not an ESCAPE clause was specified.
load_extension(X) load_extension(X,Y) | The load_extension(X,Y) function loads SQLite extensions out of the shared library file named X using the entry point Y. The result of load_extension() is always a NULL. If Y is omitted then the default entry point of sqlite3_extension_init is used. The load_extension() function raises an exception if the extension fails to load or initialize correctly. The load_extension() function will fail if the extension attempts to modify or delete a SQL function or collating sequence. The extension can add new functions or collating sequences, but cannot modify or delete existing functions or collating sequences because those functions and/or collating sequences might be used elsewhere in the currently running SQL statement. To load an extension that changes or deletes functions or collating sequences, use the sqlite3_load_extension() C-language API.
lower(X) | The lower(X) function returns a copy of string X with all ASCII characters converted to lower case. The default built-in lower() function works for ASCII characters only. To do case conversions on non-ASCII characters, load the ICU extension.
ltrim(X) ltrim(X,Y) | The ltrim(X,Y) function returns a string formed by removing any and all characters that appear in Y from the left side of X. If the Y argument is omitted, ltrim(X) removes spaces from the left side of X.
max(X,Y,...) | The multi-argument max() function returns the argument with the maximum value, or return NULL if any argument is NULL. The multi-argument max() function searches its arguments from left to right for an argument that defines a collating function and uses that collating function for all string comparisons. If none of the arguments to max() define a collating function, then the BINARY collating function is used. Note that max() is a simple function when it has 2 or more arguments but operates as an aggregate function if given only a single argument.
min(X,Y,...) | The multi-argument min() function returns the argument with the minimum value. The multi-argument min() function searches its arguments from left to right for an argument that defines a collating function and uses that collating function for all string comparisons. If none of the arguments to min() define a collating function, then the BINARY collating function is used. Note that min() is a simple function when it has 2 or more arguments but operates as an aggregate function if given only a single argument.
nullif(X,Y) | The nullif(X,Y) function returns its first argument if the arguments are different and NULL if the arguments are the same. The nullif(X,Y) function searches its arguments from left to right for an argument that defines a collating function and uses that collating function for all string comparisons. If neither argument to nullif() defines a collating function then the BINARY is used.
quote(X) | The quote(X) function returns a string which is the value of its argument suitable for inclusion into another SQL statement. Strings are surrounded by single-quotes with escapes on interior quotes as needed. BLOBs are encoded as hexadecimal literals.
random() | The random() function returns a pseudo-random integer between -9223372036854775808 and +9223372036854775807.
randomblob(N) | The randomblob(N) function return an N-byte blob containing pseudo-random bytes. If N is less than 1 then a 1-byte random blob is returned. Hint: applications can generate globally unique identifiers using this function together with hex() and/or lower() like this: hex(randomblob(16)) lower(hex(randomblob(16)))
replace(X,Y,Z) | The replace(X,Y,Z) function returns a string formed by substituting string Z for every occurrance of string Y in string X. The BINARY collating sequence is used for comparisons. If Y is an empty string then return X unchanged. If Z is not initially a string, it is cast to a UTF-8 string prior to processing.
round(X) round(X,Y) | The round(X,Y) function returns a string representation of the floating-point value X rounded to Y digits to the right of the decimal point. If the Y argument is omitted, the X value is truncated to an integer.
rtrim(X) rtrim(X,Y) | The rtrim(X,Y) function returns a string formed by removing any and all characters that appear in Y from the right side of X. If the Y argument is omitted, rtrim(X) removes spaces from the right side of X.
soundex(X) | The soundex(X) function returns a string that is the soundex encoding of the string X. The string "?000" is returned if the argument is NULL or contains no ASCII alphabetic characters. This function is omitted from SQLite by default. It is only available if the SQLITE_SOUNDEX compile-time option is used when SQLite is built.
sqlite_source_id() | The sqlite_source_id() function returns a string that identifies the specific version of the source code that was used to build the SQLite library. The string returned by sqlite_source_id() begins with the date and time that the source code was checked in and is follows by an SHA1 hash that uniquely identifies the source tree. This function is an SQL wrapper around the sqlite3_sourceid() C interface.
sqlite_version() | The sqlite_version() function returns the version string for the SQLite library that is running. This function is an SQL wrapper around the sqlite3_libversion() C-interface.
substr(X,Y,Z) substr(X,Y) | The substr(X,Y,Z) function returns a substring of input string X that begins with the Y-th character and which is Z characters long. If Z is omitted then substr(X,Y) returns all character through the end of the string X beginning with the Y-th. The left-most character of X is number 1. If Y is negative the the first character of the substring is found by counting from the right rather than the left. If Z is negative then the abs(Z) characters preceeding the Y-th character are returned. If X is string then characters indices refer to actual UTF-8 characters. If X is a BLOB then the indices refer to bytes.
total_changes() | The total_changes() function returns the number of row changes caused by INSERT, UPDATE or DELETE statements since the current database connection was opened. This function is a wrapper around the sqlite3_total_changes() C/C++ interface.
trim(X) trim(X,Y) | The trim(X,Y) function returns a string formed by removing any and all characters that appear in Y from both ends of X. If the Y argument is omitted, trim(X) removes spaces from both ends of X.
typeof(X) | The typeof(X) function returns a string that indicates the datatype of the expression X: "null", "integer", "real", "text", or "blob".
upper(X) | The upper(X) function returns a copy of input string X in which all lower-case ASCII characters are converted to their upper-case equivalent.
zeroblob(N) | The zeroblob(N) function returns a BLOB consisting of N bytes of 0x00. SQLite manages these zeroblobs very efficiently. Zeroblobs can be used to reserve space for a BLOB that is later written using incremental BLOB I/O. This SQL function is implemented using the sqlite3_result_zeroblob() routine from the C/C++ interface.