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4 minutes read
To merge specific cells in a table in Oracle, you can use the UPDATE statement with the CONCAT function. First, identify the specific cells you want to merge by specifying the rows and columns in the WHERE clause of the UPDATE statement. Then, use the CONCAT function to merge the data in the specified cells.
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To compare two Arabic strings in Oracle, you can use the NLS_SORT parameter to specify the sorting rules for Arabic characters. By using NLS_SORT=ARABIC, Oracle will use the Arabic sorting rules for comparing strings. You can use the COLLATE clause in the SELECT statement to compare two Arabic strings using the defined sorting rules. Additionally, you can use functions like NLS_LOWER or NLS_UPPER to convert the Arabic strings to lowercase or uppercase before comparing them.
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To join aggregated data from one table to another in Oracle, you can use a subquery in the FROM clause to calculate the aggregate values and then join the result with the target table.For example, you can calculate the total sales amount for each customer from a sales table and then join this aggregate data with a customer table to get additional information about the customers.You can use a query like this:SELECT c.customer_id, c.customer_name, s.
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To get the first line of a string in an Oracle query, you can use the SUBSTR function in combination with the INSTR function. The INSTR function can be used to find the position of the first occurrence of a specific character, such as a newline character. Once you have the position of the newline character, you can use the SUBSTR function to extract the first line of the string.
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To compare two sets of rows in Oracle, you can use the MINUS operator or the INTERSECT operator.MINUS operator - This operator is used to identify rows in the first query that are not present in the second query. For example:SELECT column1, column2 FROM table1 MINUS SELECT column1, column2 FROM table2;INTERSECT operator - This operator is used to identify rows that are common in both queries.
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To prevent "bad" dates in Oracle, it is important to ensure that date columns are properly defined in the database with the appropriate data type (such as DATE) to avoid any formatting or conversion issues. Additionally, validating user input on date fields before inserting or updating records can help prevent incorrect or invalid dates from being entered.
4 minutes read
To update a column using select in Oracle, you can use the UPDATE statement with a subquery that selects the values you want to update. The syntax for this would be:UPDATE table_name SET column_name = (SELECT new_value FROM other_table WHERE condition);In this statement, you need to specify the table name, the column you want to update, the new value you want to set, the table from which you want to select the new value, and any conditions that need to be met for the update to occur.
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A trigger in Oracle is a type of stored procedure that is automatically executed in response to certain events occurring in a database. These events can include actions such as inserting, updating, or deleting rows in a table. Triggers can be used to enforce business rules, perform data validation, or automate certain tasks.To create a trigger in Oracle, you first need to define the trigger's name, timing (BEFORE or AFTER), event (INSERT, UPDATE, DELETE), and scope (ROW or STATEMENT).
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To join two tables in Oracle SQL, you use the JOIN keyword in your query. The most common type of join is the INNER JOIN, which returns rows when there is at least one match in both tables.To perform an INNER JOIN, you specify the tables you want to join and the columns you want to join on using the ON keyword. For example:SELECT * FROM table1 JOIN table2 ON table1.column_name = table2.
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To parse an XML array in Oracle, you can use the XMLTable function along with XQuery expressions to extract the values from the array. The XMLTable function converts the XML data into relational rows and columns, making it easier to query and manipulate.You can specify the XML array structure in the XQuery expression within the XMLTable function to extract the desired elements or attributes from the array.