Posts (page 83)
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2 min readIn PostgreSQL, you can call a function from another schema by specifying the schema name when calling the function. For example, if you have a function named my_function in a schema named my_schema, you can call it from another schema using the following syntax: SELECT my_schema.my_function(). By specifying the schema name before the function name, PostgreSQL will be able to locate and execute the function from the specified schema.
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5 min readTo convert a canvas to a PNG file, you can use the HTMLCanvasElement.toDataURL() method in JavaScript. First, you need to create a canvas element in your HTML document and draw something on it using the canvas drawing API. Once you have finalized your design on the canvas, you can use the toDataURL() method to get a data URL representing the contents of the canvas. This data URL can then be converted to a PNG file by extracting the base64-encoded data and saving it as a .
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7 min readTo import a CSV file with many columns to PostgreSQL, you can use the \copy command in psql or the COPY command in SQL. First, make sure that the CSV file is formatted correctly and contains headers for each column. Then, create a table in your PostgreSQL database with columns that match the headers in the CSV file. You can use the CREATE TABLE command to do this.Once you have your table set up, you can use the COPY or \copy command to import the CSV file.
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4 min readTo change the size of a canvas, you can simply adjust the width and height properties of the canvas element in HTML using CSS. You can either set a specific size in pixels, or use percentages for a responsive design. Additionally, you can also dynamically change the canvas size using JavaScript by updating the width and height attributes of the canvas element. Remember to also adjust the size of the drawing context to match the new canvas size in order to prevent distortion of your drawings.
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4 min readTo convert UTC time into IST (Indian Standard Time) in PostgreSQL, you can use the AT TIME ZONE function. You can do this by adding or subtracting hours as per the time difference between UTC and IST.
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5 min readTo insert values into an already existing table in PostgreSQL, you can use the INSERT INTO command. The basic syntax is:INSERT INTO table_name (column1, column2, ...) VALUES (value1, value2, ...);Replace table_name with the name of the existing table you want to insert values into. List the columns you want to insert data into within parentheses, separated by commas. Then list the corresponding values in the VALUES clause, also separated by commas.
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5 min readTo reload the PostgreSQL configuration, you can use the pg_ctl utility with the reload option. This command sends a SIGHUP signal to the PostgreSQL server process, prompting it to reload the configuration files without shutting down and restarting the server. This allows you to make changes to the configuration files, such as postgresql.conf or pg_hba.conf, and apply them without having to restart the entire server.
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4 min readTo properly insert data from stdin in PostgreSQL, you can use the COPY command. You can redirect the standard input to the COPY command by using the psql command line tool.First, create a table in your database that matches the format of the data you want to insert. Then, use the following command to copy data from stdin into the table:COPY table_name (column1, column2, ...) FROM STDIN;Next, paste or type the data you want to insert into the terminal window.
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5 min readTo select a range of the last month in PostgreSQL, you can use the current date function to get the current date and time, and then use the interval function to subtract one month from the current date.
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5 min readTo rename a column named 'user' in PostgreSQL, you can use the ALTER TABLE statement along with the RENAME COLUMN keyword.
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4 min readTo get a JSON property value using PostgreSQL, you can use the -> operator to navigate through the JSON data.
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5 min readTo calculate the dividend yield for dividend reinvestment plans (DRIPs), you first need to determine the annual dividend amount per share. This information can usually be found on the company's website or in their financial reports.Next, you will need to find the current market price of the stock. This can be easily obtained by checking a financial news website or using a stock market app.