manual.texi More keyword capping. (49a188f7) · Commits · Software / OSDI20 Artifacts / mariadb

Docs/manual.texi

+63 −62

Original line number	Diff line number	Diff line
		@@ -32415,7 +32415,7 @@ mysql> SELECT BIT_COUNT(29);
		Returns the current database name:

		@example
		mysql> select DATABASE();
		mysql> SELECT DATABASE();
		-> 'test'
		@end example

		@@ -32430,7 +32430,7 @@ If there is no current database, @code{DATABASE()} returns the empty string.
		Returns the current MySQL user name:

		@example
		mysql> select USER();
		mysql> SELECT USER();
		-> 'davida@@localhost'
		@end example

		@@ -32439,7 +32439,7 @@ as well as the user name. You can extract just the user name part like this
		(which works whether or not the value includes a hostname part):

		@example
		mysql> select substring_index(USER(),"@@",1);
		mysql> SELECT SUBSTRING_INDEX(USER(),"@@",1);
		-> 'davida'
		@end example

		@@ -32450,7 +32450,7 @@ the function that is used for encrypting MySQL passwords for storage
		in the @code{Password} column of the @code{user} grant table:

		@example
		mysql> select PASSWORD('badpwd');
		mysql> SELECT PASSWORD('badpwd');
		-> '7f84554057dd964b'
		@end example

		@@ -32470,7 +32470,7 @@ Encrypt @code{str} using the Unix @code{crypt()} system call. The
		(As of MySQL Version 3.22.16, @code{salt} may be longer than two characters.):

		@example
		mysql> select ENCRYPT("hello");
		mysql> SELECT ENCRYPT("hello");
		-> 'VxuFAJXVARROc'
		@end example

		@@ -32501,7 +32501,7 @@ Calculates a MD5 checksum for the string. Value is returned as a 32 long
		hex number that may, for example, be used as a hash key:

		@example
		mysql> select MD5("testing");
		mysql> SELECT MD5("testing");
		-> 'ae2b1fca515949e5d54fb22b8ed95575'
		@end example

		@@ -32594,7 +32594,7 @@ Returns the last automatically generated value that was inserted into an
		@xref{mysql_insert_id,, @code{mysql_insert_id()}}.

		@example
		mysql> select LAST_INSERT_ID();
		mysql> SELECT LAST_INSERT_ID();
		-> 195
		@end example

		@@ -32617,14 +32617,14 @@ auto_increment value. This can be used to simulate sequences:
		First create the table:

		@example
		mysql> create table sequence (id int not null);
		mysql> insert into sequence values (0);
		mysql> CREATE TABLE sequence (id INT NOT NULL);
		mysql> INSERT INTO sequence VALUES (0);
		@end example

		Then the table can be used to generate sequence numbers like this:

		@example
		mysql> update sequence set id=LAST_INSERT_ID(id+1);
		mysql> UPDATE sequence SET id=LAST_INSERT_ID(id+1);
		@end example

		You can generate sequences without calling @code{LAST_INSERT_ID()}, but the
		@@ -32648,11 +32648,11 @@ to @code{D} decimals. If @code{D} is @code{0}, the result will have no
		decimal point or fractional part:

		@example
		mysql> select FORMAT(12332.123456, 4);
		mysql> SELECT FORMAT(12332.123456, 4);
		-> '12,332.1235'
		mysql> select FORMAT(12332.1,4);
		mysql> SELECT FORMAT(12332.1,4);
		-> '12,332.1000'
		mysql> select FORMAT(12332.2,0);
		mysql> SELECT FORMAT(12332.2,0);
		-> '12,332'
		@end example

		@@ -32661,7 +32661,7 @@ mysql> select FORMAT(12332.2,0);
		Returns a string indicating the MySQL server version:

		@example
		mysql> select VERSION();
		mysql> SELECT VERSION();
		-> '3.23.13-log'
		@end example

		@@ -32674,7 +32674,7 @@ Returns the connection id (@code{thread_id}) for the connection.
		Every connection has its own unique id:

		@example
		mysql> select CONNECTION_ID();
		mysql> SELECT CONNECTION_ID();
		-> 1
		@end example

		@@ -32693,13 +32693,13 @@ the same name; clients that agree on a given lock string name can use the
		string to perform cooperative advisory locking:

		@example
		mysql> select GET_LOCK("lock1",10);
		mysql> SELECT GET_LOCK("lock1",10);
		-> 1
		mysql> select GET_LOCK("lock2",10);
		mysql> SELECT GET_LOCK("lock2",10);
		-> 1
		mysql> select RELEASE_LOCK("lock2");
		mysql> SELECT RELEASE_LOCK("lock2");
		-> 1
		mysql> select RELEASE_LOCK("lock1");
		mysql> SELECT RELEASE_LOCK("lock1");
		-> NULL
		@end example

		@@ -32727,7 +32727,7 @@ processes the expression. The result value is always @code{0}. The intended
		use is in the @code{mysql} client, which reports query execution times:

		@example
		mysql> select BENCHMARK(1000000,encode("hello","goodbye"));
		mysql> SELECT BENCHMARK(1000000,ENCODE("hello","goodbye"));
		+----------------------------------------------+
		\| BENCHMARK(1000000,encode("hello","goodbye")) \|
		+----------------------------------------------+
		@@ -32747,7 +32747,7 @@ Given a numeric network address (4 or 8 byte), returns the dotted-quad
		representation of the address as a string:

		@example
		mysql> select INET_NTOA(3520061480);
		mysql> SELECT INET_NTOA(3520061480);
		-> "209.207.224.40"
		@end example

		@@ -32758,7 +32758,7 @@ returns an integer that represents the numeric value of the address.
		Addresses may be 4 or 8 byte addresses:

		@example
		mysql> select INET_ATON("209.207.224.40");
		mysql> SELECT INET_ATON("209.207.224.40");
		-> 3520061480
		@end example

		@@ -32784,7 +32784,7 @@ Returns the number of rows that the last @code{SELECT SQL_CALC_FOUND_ROWS ...}
		command would have returned, if wasn't restricted with @code{LIMIT}.

		@example
		mysql> SELECT SQL_CALC_FOUND_ROWS * FROM table_name
		mysql> SELECT SQL_CALC_FOUND_ROWS * FROM tbl_name
		WHERE id > 100 LIMIT 10;
		mysql> SELECT FOUND_ROWS();
		@end example
		@@ -32833,7 +32833,7 @@ other columns are retrieved, and there is no @code{WHERE} clause.
		For example:

		@example
		mysql> select COUNT(*) from student;
		mysql> SELECT COUNT(*) FROM student;
		@end example

		@findex COUNT(DISTINCT)
		@@ -32842,7 +32842,7 @@ mysql> select COUNT(*) from student;
		Returns a count of the number of different non-@code{NULL} values:

		@example
		mysql> select COUNT(DISTINCT results) from student;
		mysql> SELECT COUNT(DISTINCT results) FROM student;
		@end example

		In MySQL you can get the number of distinct expression
		@@ -32855,8 +32855,8 @@ inside @code{CODE(DISTINCT ...)}.
		Returns the average value of @code{expr}:

		@example
		mysql> select student_name, AVG(test_score)
		-> from student
		mysql> SELECT student_name, AVG(test_score)
		-> FROM student
		-> GROUP BY student_name;
		@end example

		@@ -32869,8 +32869,8 @@ Returns the minimum or maximum value of @code{expr}. @code{MIN()} and
		minimum or maximum string value. @xref{MySQL indexes}.

		@example
		mysql> select student_name, MIN(test_score), MAX(test_score)
		-> from student
		mysql> SELECT student_name, MIN(test_score), MAX(test_score)
		-> FROM student
		-> GROUP BY student_name;
		@end example

		@@ -32909,9 +32909,9 @@ grouping on unnecessary items. For example, you don't need to group on
		@code{customer.name} in the following query:

		@example
		mysql> select order.custid,customer.name,max(payments)
		-> from order,customer
		-> where order.custid = customer.custid
		mysql> SELECT order.custid,customer.name,max(payments)
		-> FROM order,customer
		-> WHERE order.custid = customer.custid
		-> GROUP BY order.custid;
		@end example

		@@ -33023,8 +33023,8 @@ is used as the expression's column name and can be used with
		@code{ORDER BY} or @code{HAVING} clauses. For example:

		@example
		mysql> select concat(last_name,', ',first_name) AS full_name
		from mytable ORDER BY full_name;
		mysql> SELECT CONCAT(last_name,', ',first_name) AS full_name
		FROM mytable ORDER BY full_name;
		@end example

		@item
		@@ -33070,10 +33070,10 @@ forms.
		A table reference may be aliased using @code{tbl_name [AS] alias_name}:

		@example
		mysql> select t1.name, t2.salary from employee AS t1, info AS t2
		-> where t1.name = t2.name;
		mysql> select t1.name, t2.salary from employee t1, info t2
		-> where t1.name = t2.name;
		mysql> SELECT t1.name, t2.salary FROM employee AS t1, info AS t2
		-> WHERE t1.name = t2.name;
		mysql> SELECT t1.name, t2.salary FROM employee t1, info t2
		-> WHERE t1.name = t2.name;
		@end example

		@item
		@@ -33082,11 +33082,11 @@ Columns selected for output may be referred to in @code{ORDER BY} and
		positions. Column positions begin with 1:

		@example
		mysql> select college, region, seed from tournament
		mysql> SELECT college, region, seed FROM tournament
		-> ORDER BY region, seed;
		mysql> select college, region AS r, seed AS s from tournament
		mysql> SELECT college, region AS r, seed AS s FROM tournament
		-> ORDER BY r, s;
		mysql> select college, region, seed from tournament
		mysql> SELECT college, region, seed FROM tournament
		-> ORDER BY 2, 3;
		@end example

		@@ -33106,26 +33106,26 @@ the client, with no optimisation. Don't use @code{HAVING} for items that
		should be in the @code{WHERE} clause. For example, do not write this:

		@example
		mysql> select col_name from tbl_name HAVING col_name > 0;
		mysql> SELECT col_name FROM tbl_name HAVING col_name > 0;
		@end example

		Write this instead:

		@example
		mysql> select col_name from tbl_name WHERE col_name > 0;
		mysql> SELECT col_name FROM tbl_name WHERE col_name > 0;
		@end example

		In MySQL Version 3.22.5 or later, you can also write queries like this:

		@example
		mysql> select user,max(salary) from users
		mysql> SELECT user,MAX(salary) FROM users
		-> group by user HAVING max(salary)>10;
		@end example

		In older MySQL versions, you can write this instead:

		@example
		mysql> select user,max(salary) AS sum from users
		mysql> SELECT user,MAX(salary) AS sum FROM users
		-> group by user HAVING sum>10;
		@end example

		@@ -33230,13 +33230,13 @@ return, the second specifies the maximum number of rows to return.
		The offset of the initial row is 0 (not 1):

		@example
		mysql> select * from table LIMIT 5,10; # Retrieve rows 6-15
		mysql> SELECT * FROM table LIMIT 5,10; # Retrieve rows 6-15
		@end example

		If one argument is given, it indicates the maximum number of rows to return:

		@example
		mysql> select * from table LIMIT 5; # Retrieve first 5 rows
		mysql> SELECT * FROM table LIMIT 5; # Retrieve first 5 rows
		@end example

		In other words, @code{LIMIT n} is equivalent to @code{LIMIT 0,n}.
		@@ -33382,8 +33382,8 @@ A table reference may be aliased using @code{tbl_name AS alias_name} or
		@code{tbl_name alias_name}:

		@example
		mysql> select t1.name, t2.salary from employee AS t1, info AS t2
		-> where t1.name = t2.name;
		mysql> SELECT t1.name, t2.salary FROM employee AS t1, info AS t2
		-> WHERE t1.name = t2.name;
		@end example

		@item
		@@ -33397,9 +33397,9 @@ If there is no matching record for the right table in the @code{ON} or
		records in a table that have no counterpart in another table:

		@example
		mysql> select table1.* from table1
		mysql> SELECT table1.* FROM table1
		-> LEFT JOIN table2 ON table1.id=table2.id
		-> where table2.id is NULL;
		-> WHERE table2.id IS NULL;
		@end example

		This example finds all rows in @code{table1} with an @code{id} value that is
		@@ -34293,7 +34293,7 @@ The @code{IGNORE number LINES} option can be used to ignore a header of
		column names at the start of the file:

		@example
		mysql> LOAD DATA INFILE "/tmp/file_name" into table test IGNORE 1 LINES;
		mysql> LOAD DATA INFILE "/tmp/file_name" INTO TABLE test IGNORE 1 LINES;
		@end example

		When you use @code{SELECT ... INTO OUTFILE} in tandem with @code{LOAD
		@@ -35089,9 +35089,9 @@ MySQL will create new fields for all elements in the
		@code{SELECT}. For example:

		@example
		mysql> CREATE TABLE test (a int not null auto_increment,
		-> primary key (a), key(b))
		-> TYPE=MyISAM SELECT b,c from test2;
		mysql> CREATE TABLE test (a INT NOT NULL AUTO_INCREMENT,
		-> PRIMARY KEY (a), KEY(b))
		-> TYPE=MyISAM SELECT b,c FROM test2;
		@end example

		This will create a @code{MyISAM} table with three columns, a, b, and c.
		@@ -35100,18 +35100,18 @@ the right side of the table, not overlapped onto it. Take the following
		example:

		@example
		mysql> select * from foo;
		mysql> SELECT * FROM foo;
		+---+
		\| n \|
		+---+
		\| 1 \|
		+---+

		mysql> create table bar (m int) select n from foo;
		mysql> CREATE TABLE bar (m INT) SELECT n FROM foo;
		Query OK, 1 row affected (0.02 sec)
		Records: 1 Duplicates: 0 Warnings: 0

		mysql> select * from bar;
		mysql> SELECT * FROM bar;
		+------+---+
		\| m \| n \|
		+------+---+
		@@ -35129,7 +35129,7 @@ possible. If you want to have indexes in the created table, you should
		specify these before the @code{SELECT} statement:

		@example
		mysql> create table bar (unique (n)) select n from foo;
		mysql> CREATE TABLE bar (UNIQUE (n)) SELECT n FROM foo;
		@end example

		If any errors occur while copying the data to the table, it will
		@@ -35915,9 +35915,9 @@ example shown below requires @code{LOCK TABLES} in order to execute safely:

		@example
		mysql> LOCK TABLES trans READ, customer WRITE;
		mysql> select sum(value) from trans where customer_id= some_id;
		mysql> update customer set total_value=sum_from_previous_statement
		-> where customer_id=some_id;
		mysql> SELECT SUM(value) FROM trans WHERE customer_id=some_id;
		mysql> UPDATE customer SET total_value=sum_from_previous_statement
		-> WHERE customer_id=some_id;
		mysql> UNLOCK TABLES;
		@end example

		@@ -37233,6 +37233,7 @@ INSERT INTO t2 (message) VALUES ("Testing"),("table"),("t2");
		CREATE TABLE total (a INT NOT NULL, message CHAR(20), KEY(a))
		TYPE=MERGE UNION=(t1,t2) INSERT_METHOD=LAST;
		@end example
		@c CAPPING DONE TO HERE

		Note that we didn't create a @code{UNIQUE} or @code{PRIMARY KEY} in the
		@code{total} table as the key isn't going to be unique in the @code{total}