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Displaying posts with tag: MySQL data type (reset)
Apr
20
2010
Choosing the right data type makes a big difference
Posted by Venu Anuganti on Tue 20 Apr 2010 05:37 UTC
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Today evening one of my friend asked me in the IM to look into one of his production server where a query was taking ~11 seconds to run on 20 million row table, even though the query is using the right index and the plan as shown below:

mysql> explain SELECT channel, COUNT(channel) AS visitors FROM [...]

Jul
05
2008
MySQL – Choose exact numeric data type
Posted by Mahmud Ahsan on Sat 05 Jul 2008 07:12 UTC
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When we use a relational database system, we should know some important things. Numeric data type is very essential for a table. Here I describe some important points of Numeric Data type in MySQL:

MySQL has 9 numeric data types

  • Integer:            TINYINT, SMALLINT, MEDIUMINT, INT, BIGINT
  • Floating Point:  FLOAT, DOUBLE
  • Fixed Point:      DECIMAL
  • Other:              BIT, (ENUM maybe)‫‏‬

Some poor design:

  • INT(1)‫‏‬
  • BIGINT AUTO_INCREMENT
  • no UNSIGNED used
  • DECIMAL(31,0)‫‏‬

INT(1) – 1 does not mean 1 digit.   (1) represents client output display format only. INT is 4 Bytes. TINYINT is 1 Byte …

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