Posts - Page 81 (page 81)
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6 min readTo cast a string to an integer in PHP with PostgreSQL, you can use the ::integer cast in your SQL query. For example: $stringValue = "123"; $sql = "SELECT $stringValue::integer as int_value"; $result = pg_query($conn, $sql); $row = pg_fetch_assoc($result); $intValue = $row['int_value']; In this example, we are casting the string value "123" to an integer using the ::integer cast in the SQL query.
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4 min readTo change the tablespace for a partition in PostgreSQL, you can use the ALTER TABLE command with the SET TABLESPACE option. First, make sure you have the necessary privileges to alter the table. Then, use the following SQL statement:ALTER TABLE table_name SET TABLESPACE new_tablespace;Replace "table_name" with the name of the table containing the partition you want to move, and "new_tablespace" with the name of the new tablespace where you want to move the partition.
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10 min readTo create a database from a .sql file with PostgreSQL, you can use the command line tool called psql. First, make sure you have PostgreSQL installed on your system. Then, open a terminal and navigate to the directory where your .sql file is located.Next, start the psql command line tool by typing 'psql' in the terminal.
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4 min readTo select data within the last 30 days from a specific date in PostgreSQL, you can use the current_date function to get the current date and then subtract 30 days from it using the interval keyword.
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4 min readTo set up default timestamp to char conversion in PostgreSQL, you can use the TO_CHAR function. This function allows you to convert a timestamp data type to a character string with a specific format. You can specify the desired format using a pattern of special characters.
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5 min readUpdating 10 million records in PostgreSQL can be done efficiently by using batching or chunking techniques. Instead of updating all records in a single query, it is recommended to break down the updates into smaller batches to prevent locking issues and optimize performance.One approach is to use a loop to update records in batches of a certain size, such as 1000 or 10000, depending on the specific requirements and system limitations.
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2 min readTo split a string in PostgreSQL using a procedure, you can write a user-defined function that takes the string as input and returns an array of split values. Within the function, you can use the string_to_array function along with a delimiter to split the string into an array of substrings. The procedure can then be called with the input string to get the desired output.[rating:e727dd3b-20e7-430f-ba0b-7c16ada6dc22]How to split a string into multiple columns in PostgreSQL.
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4 min readTo run multiple insert statements in a transaction in PostgreSQL, you can use the BEGIN, COMMIT, and ROLLBACK keywords to start, end, and cancel a transaction, respectively. Within the transaction block, you can include multiple insert statements to be executed as a single atomic operation. This ensures that if any of the insert statements fail, the transaction can be rolled back and none of the data will be committed to the database.
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6 min readIn PostgreSQL, you can store values from one procedure to another by using variables. You can declare variables within a procedure by using the DECLARE keyword followed by the variable name and data type. You can then assign values to these variables using the := operator.After storing a value in a variable in one procedure, you can pass that value to another procedure by either passing it as a parameter or by using a global variable.
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3 min readTo copy a CSV file into a Postgres Docker container, you can use the COPY command in a SQL statement. First, make sure the CSV file is accessible from the host machine running the Docker container.Next, start the Postgres Docker container and connect to the database using a client like psql. Then, you can run the COPY command in SQL to import the CSV file into a table.For example: COPY table_name FROM '/path/to/csv/file.
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5 min readTo calculate a percentage as an integer in PostgreSQL, you can use the following formula:(int)((value1 / value2) * 100)Where value1 is the numerator and value2 is the denominator. This formula calculates the percentage as a decimal value, which is then cast to an integer using the "int" function to get the final result as an integer.For example, if you want to calculate the percentage of 20 out of 50 as an integer:(int)((20 / 50) * 100) = (int)(0.
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4 min readTo convert a JSON array to a JSON object in PostgreSQL, you can use the json_object() function. This function allows you to create a JSON object from key-value pairs.You can first unnest the JSON array using the json_array_elements_text() function to get the elements of the array as text values. Then, you can use the json_object() function to construct a JSON object from these elements.