You can check the mysql function string_replace here http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_replace
Ex:
mysql> SELECT REPLACE(‘www.mysql.com‘, ‘w’, ‘Wo’);
output: ‘WoWoWo.mysql.com’
Or you can also do it on UPDATE statements like this
UPDATE table SET table_field=REPLACE(table_field, search_string, replace_value_here)
PROBLEM: How to modify or change the database’s charset
SOLUTION; charset of dbase – to change this ALTER DATABASE
Indexes are organized versions of specific columns in your tables. MySQL uses indexes to facilitate quick retrieval of records. With indexes, MySQL can jump directly to the records you want. Without any indexes, MySQL has to read the entire data file to find the correct record(s). Here’s an example.
Suppose we created a table called “people”:
CREATE TABLE people (
peopleid SMALLINT NOT NULL,
name CHAR(50) NOT NULL
);
Then we insert 1000 different names into the table in a completely random, non-alphabetic order. A small portion of the data file may be represented like this:
There are several types of indexes to choose from in MySQL:
[Note: Full query lists and examples can be found at the end of this article.]
CREATE INDEX name_of_index ON tablename (columns_to_index);), altering the table (ALTER TABLE tablename ADD INDEX [name_of_index] (columns_to_index);), or when creating the table (CREATE TABLE tablename ( [...], INDEX [name_of_index] (columns_to_index) );).CREATE UNIQUE INDEX name_of_index ON tablename (columns_to_index);), altering the table (ALTER TABLE tablename ADD UNIQUE [name_of_index] (columns_to_index);) or when creating the table (CREATE TABLE tablename ( [...], UNIQUE [name_of_index] (columns_to_index) );).“PRIMARYâ€. If you have used AUTO_INCREMENT columns, you’re probably familiar with these. These indexes are almost always added when creating the table (CREATE TABLE tablename ( [...], PRIMARY KEY (columns_to_index) );), but may also be added by altering the table (ALTER TABLE tablename ADD PRIMARY KEY (columns_to_index);). Note that you may only have one primary key per table.UNIX_TIMESTAMP(), UNIX_TIMESTAMP(date)
If called with no argument, returns a Unix timestamp (seconds since '1970-01-01 00:00:00' UTC) as an unsigned integer. If UNIX_TIMESTAMP() is called with a date argument, it returns the value of the argument as seconds since '1970-01-01 00:00:00' UTC. date may be a DATE string, a DATETIME string, a TIMESTAMP, or a number in the format YYMMDD or YYYYMMDD. The server interprets date as a value in the current time zone and converts it to an internal value in UTC. Clients can set their time zone as described in Section 9.7, “MySQL Server Time Zone Supportâ€.
mysql>SELECT UNIX_TIMESTAMP();-> 1196440210 mysql>SELECT UNIX_TIMESTAMP('2007-11-30 10:30:19');-> 1196440219
When UNIX_TIMESTAMP() is used on a TIMESTAMP column, the function returns the internal timestamp value directly, with no implicit “string-to-Unix-timestamp†conversion. If you pass an out-of-range date to UNIX_TIMESTAMP(), it returns 0.
Note: If you use UNIX_TIMESTAMP() and FROM_UNIXTIME() to convert between TIMESTAMP values and Unix timestamp values, the conversion is lossy because the mapping is not one-to-one in both directions. For example, due to conventions for local time zone changes, it is possible for two UNIX_TIMESTAMP() to map two TIMESTAMP values to the same Unix timestamp value. FROM_UNIXTIME() will map that value back to only one of the original TIMESTAMP values. Here is an example, using TIMESTAMP values in the CET time zone:
mysql>SELECT UNIX_TIMESTAMP('2005-03-27 03:00:00');+---------------------------------------+ | UNIX_TIMESTAMP('2005-03-27 03:00:00') | +---------------------------------------+ | 1111885200 | +---------------------------------------+ mysql>SELECT UNIX_TIMESTAMP('2005-03-27 02:00:00');+---------------------------------------+ | UNIX_TIMESTAMP('2005-03-27 02:00:00') | +---------------------------------------+ | 1111885200 | +---------------------------------------+ mysql>SELECT FROM_UNIXTIME(1111885200);+---------------------------+ | FROM_UNIXTIME(1111885200) | +---------------------------+ | 2005-03-27 03:00:00 | +---------------------------+
If you want to subtract UNIX_TIMESTAMP() columns, you might want to cast the result to signed integers. See Section 11.9, “Cast Functions and Operatorsâ€.
SOURCE: http://dev.mysql.com/doc/refman/5.0/en/cast-functions.html
The DECIMAL and NUMERIC data types are used to store exact numeric data values. In MySQL, NUMERIC is implemented as DECIMAL. These types are used to store values for which it is important to preserve exact precision, for example with monetary data.
Related article: http://dreamluverz.com/developers-tools/mysql/double-float-decimal