Oracle Dates and Times. Resources Database Systems: The Complete Book by Hector Garcia, Jeff Ullman, and Jennifer Widom. A First Course in Database Systems by Jeff Ullman and Jennifer Widom. Gradiance SQL Tutorial. Overview Oracle supports both date and time, albeit differently from the SQL2 standard. The DATE type is used in the same way as other built-in types such as INT. Create table x(a int, b date); DATE Format When a DATE value is displayed, Oracle must first convert that value from the special internal format to a printable string. Select b from x; you will see something like: Whenever a DATE value is displayed, Oracle will call TO_CHAR automatically with the default DATE format. SELECT TO_CHAR(b, 'YYYY/MM/DD') AS b FROM x; returns the result: The general usage of TO_CHAR is: TO_CHAR(<date>, '<format>') where the <format> string can be formed from over 40 options.
You have just learned how to output a DATE value using TO_CHAR. Insert into x values(99, '31-may-98'); Alternatively, you may use TO_DATE explicitly: CREATE a table from another table. Learn how to use the SQL CREATE TABLE AS statement with syntax and examples. Description You can also use the SQL CREATE TABLE AS statement to create a table from an existing table by copying the existing table's columns.
It is important to note that when creating a table in this way, the new table will be populated with the records from the existing table (based on the SELECT Statement). Create Table - By Copying all columns from another table Syntax The syntax for the SQL CREATE TABLE AS statement copying all of the columns is: CREATE TABLE new_table AS (SELECT * FROM old_table); Example Let's look at an example that shows how to create a table by copying all columns from another table. For Example: CREATE TABLE suppliers AS (SELECT * FROM companies WHERE id > 1000); This would create a new table called suppliers that included all columns from the companies table.
Create Table - By Copying selected columns from another table Create Table - By Copying selected columns from multiple tables. Mysql - Odd CONCAT Error with Select/Insert. MySQL concat() function < MySql Tutorial. MySQL concat() function has average rating 8 out of 10. Total 61 users rated. <<PreviousNext>> Description MySQL CONCAT() function is used to add two or more strings.
There may be one or more arguments. Syntax CONCAT (string1, string2,…) Arguments MySQL Version : 5.6 Examples of MySQL CONCAT() function One argument : mysql> SELECT CONCAT('w3resource'); +----------------------+ | CONCAT('w3resource') | +----------------------+ | w3resource | +----------------------+ 1 row in set (0.00 sec) Two or more arguments : mysql> SELECT CONCAT('w3resource','.','com'); +--------------------------------+ | CONCAT('w3resource','.','com') | +--------------------------------+ | w3resource.com | +--------------------------------+ 1 row in set (0.00 sec) One of the arguments is NULL : Numeric argument : mysql> SELECT CONCAT(102.33); +----------------+ | CONCAT(102.33) | +----------------+ | 102.33 | +----------------+ 1 row in set (0.00 sec) mysql>SELECT 'w3resource' '.' Example of MySQL CONCAT() function on columns <!
SQL Concatenate Function - 1Keydata SQL Tutorial. SQL > SQL String Functions > Concatenate Sometimes it is necessary to combine together (concatenate) the results from several different fields. Each database provides a way to do this: MySQL: CONCAT( ) Oracle: CONCAT( ), || SQL Server: + The syntax for CONCAT( ) is as follows: CONCAT (str1, str2, str3, ...) The above syntax concatenates str1, str2, str3, and any other strings together. Let's look at some examples. Table Geography Example 1 MySQL/Oracle: SELECT CONCAT(Region_Name, Store_Name) FROM Geography WHERE Store_Name = 'Boston'; Result: 'EastBoston' Example 2 Oracle: SELECT Region_Name || ' ' || Store_Name FROM Geography WHERE Store_Name = 'Boston'; 'East Boston' Example 3 SQL Server: SELECT Region_Name + ' ' + Store_Name FROM Geography WHERE Store_Name = 'Boston'; Next: SQL SUBSTRING.
V15 - Oracle SQL Tutorial - Insert data into a table. Joins. Learn how to use SQL joins with syntax, visual illustrations, and examples. Description SQL JOINS are used to retrieve data from multiple tables. A SQL JOIN is performed whenever two or more tables are joined in a SQL statement. There are 4 different types of SQL joins: SQL INNER JOIN (or sometimes called simple join) SQL LEFT OUTER JOIN (or sometimes called LEFT JOIN) SQL RIGHT OUTER JOIN (or sometimes called RIGHT JOIN) SQL FULL OUTER JOIN (or sometimes called FULL JOIN) So let's discuss SQL JOIN syntax, look at visual illustrations of SQL JOINS, and explore SQL JOIN examples.
SQL INNER JOIN (simple join) Chances are, you've already written a SQL statement that uses an SQL INNER JOIN. Syntax The syntax for the SQL INNER JOIN is: SELECT columns FROM table1 INNER JOIN table2 ON table1.column = table2.column; Visual Illustration In this visual diagram, the SQL INNER JOIN returns the shaded area: The SQL INNER JOIN would return the records where table1 and table2 intersect. Example Old Syntax. SQL Tutorials: SQL IF...ELSE Statement. SQL IF...ELSE Statement used to test a condition. IF...ELSE Statement using in execution of a Transact-SQL statement (Store Procedure or T-SQL) and Trigger.IF tests can be nested after another IF or following an ELSE. There is no limit to the number of nested levels.
IF condition is satisfied and the Boolean expression returns TRUE, it will executed IF Block Sql statement. IF condtion is not satisfied and the Boolean expression returns FALSE, it will executed ELSE Block Sql Statement query. Syntax for IF...ELSEIF ( Boolean_expression ) BEGINSql Statement BlockENDELSE BEGINSql Statement BlockENDBelow is simple example of IF...ELSE Statement With 1 IF...ELSE BlockFor Boolean_expression part, you can replace with your condition to match with your Sql query.
If your IF...ELSE Block Sql Statement only have 1 Sql query, you no need to include the BEGIN...END. Oracle Tip: Create functions to join and split strings in SQL. Learn how to take a comma delimited list of values in a single string and use it as a table of values. A common task when selecting data from a database is to take a set of values a query returns and format it as a comma delimited list.
Another task that's almost as common is the need to do the reverse: Take a comma delimited list of values in a single string and use it as a table of values. Many scripting languages, such as Perl and Python, provide functions that do this with their own language-specific list of values; so it's surprising that, as of yet, this functionality isn't a standard part of SQL functions. I've seen some pretty ugly looking code that involved complex declarations with MAX and DECODE, but that solution usually only returns a limited set of values.
With some of the new Oracle9i and above features, it's possible to do this yourself. SQL> select join(cursor(select ename from emp)) from dual; The following code will perform this function: There's another extra benefit. Create table [Oracle SQL] Prerequisites Additionally, the user needs to have enough quota on the tablespace where he wants to create the table. Heap tables Usually, if we refer to tables, we mean heap tables, although there are other types as well. A heap table is created like this: create table t ( a number, b varchar2(10) ) It is possible to create the constraints together with the create statement. Create table orders ( order_id number primary key order_dt date, cust_id references customers ) A primary key needs to have an associated (unique) index. Create table orders ( order_id number, order_dt date, cust_id references customer constraint pk_orders (order_id) using index tablespace ts_idx ) Index organized tables (IOT) create table iot_ ( a number, b varchar2(10), constraint pk_iot_ primary key (a, b) ) organization index; Global temporary tables The following example shows the difference for redo generated when using global temporary tables and "ordinary" heap tables.
Organization external Nested tables of XMLType.