where the words of the operator:
= Equal <> unequal ! = Unequal < less than <= Less than or equal > greater than > = greater than or equal between the two specified values between
After the wildcard statements like: multiple%
_ Single
Regular Expressions:
Select prod_name from products where REGEXP_LIKE(prod_name,’1000’)
The above statement indicates that the search all lines of 1000
Execution or matching the query 1000 or 2000:
Select prod_name from products where REGEXP_LIKE(prod_name,’1000|2000’)
A plurality of matching characters [], 123 matches any one of
Select prod_name from products where REGEXP_LIKE(prod_name,’[123] ton‘)
A plurality of matching characters negated, any one in addition to matching 123
Select prod_name from products where REGEXP_LIKE(prod_name,’[^123] ton‘)
Matching range matching 1-5
Select prod_name from products where REGEXP_LIKE(prod_name,’[1-5] ton‘)
Matching special characters, with the transfer \
Select prod_name from products where REGEXP_LIKE(prod_name,’\.‘)
Matching character classes:
\ d arbitrary number (equivalent to [ 0 - . 9 ]) \ D any non-numeric character (equivalent to [ ^ 0 - . 9 ]) \ W any letter or number (equivalent to [A -za-Z0- . 9 ]) \ W is any non- letters or numeric characters (equivalent to [ ^ A-zA-Z0- . 9 ]) \ S any whitespace character \ S any non-whitespace characters
Repeat metacharacters
* Zero or more matches + 1 or more matches (equivalent to { 1 }) ? 0, or a matching (equivalent to { 0 , 1 }) {} n-number of specific match {n, } hits are less than the specified range {n, m} matches
Text commonly used functions:
Length () Returns a string length of the Lower () is converted into lowercase LPAD () String with spaces on the left the LTrim () to remove the spaces left RPAD () padded with spaces to the right of the string RTrim () remove the right box the Soundex () Returns a string SOUNDEX value - and to pronounce a relationship SubString () returns the string of characters Upper () returns uppercase
Date function:
Add_Month () to add date / minus month Extract () minus the year, month, day, hour and date from the time --- very important Last_Day () returns the last day of the month Months_Beween () Returns the number of months between two month Next_Day () returns the day following the specified date Sysdate () returns the current date and time To_Date () to convert the string to a date
Note that the Extract () process parameters only YEAR, MONTH, DAY, HOUR, MINUTE, SECOND
Select * from orders where Extract(Year from order_date) = 2015
And Extract(Month from order_date) = 2