MySQL函數名稱筆記

標籤：

$conn = mysql_connect();

process language;
no-process language;
/*

SQL
DDL define
DML mainpulate
DCL control
interacitve SQL
embeded SQL

SELECT user_name,age
FROM tbl_user
WHERE age>18
key words:
CREATE TABLE
DROP TABLE
ALTER TABLE
CREATE INDEX
DROP INDEX
CREATE PROCEDURE
DROP PROCEDURE

SELECT
INSERT
UPDATE
DELETE

GRANT
REVOKE

COMMIT
ROLLBACK
-----
2. Data type:
INT type:
TINYINT 1byte
SAMILLINT 2 bytes
MEDIUMINT 3 bytes
INT 4 bytes
BIGINT 8bytes

Real number type:
FLOAT 4 bytes
DOUBLE 8 bytes
DECIMAL(20,2)

String type: >80%
VARCHAR can change
CHAR length-unchanged
TEXT >> TINYTEXT TEXT MEDIUMTEXT LONGTEXT //charset
BLOB >> TINYBLOB BLOB MEDIUMBLOB LONGBLOB //binary
DATETIME 8 bytes
TIMESTAMP 1970-1-1 Gerorg time - 2938

Select data type standard:
1. minimize
2. simple
3. index not NULL
--------

3. Common operation
add delete edit search

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MySQL函數名稱筆記