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5 min readTo modify an array under a specific JSONB key in PostgreSQL, you can use the jsonb_set function. This function allows you to specify the path to the key you want to modify and update the array under that key.
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4 min readTo filter a PostgreSQL query by date using Python, you can use the psycopg2 library to connect to the database and execute SQL queries. You can specify the date range using the WHERE clause in your query. For example, if you want to filter records that fall within a specific date range, you can use the following syntax: import psycopg2 conn = psycopg2.connect("dbname=mydb user=postgres password=secret") cur = conn.
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3 min readIn PostgreSQL, you can cast a string into an integer by using the CAST function or the :: operator. For example, if you have a string '123' and you want to convert it into an integer, you can do so by using either of the following queries:Using the CAST function: SELECT CAST('123' AS INTEGER); Using the :: operator: SELECT '123'::INTEGER; Both of these queries will convert the string '123' into an integer value of 123.
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3 min readTo join 2 columns and extract year and count in PostreSQL, you can use the following SQL query:SELECT EXTRACT(year FROM date_column) AS year, COUNT(*) AS count FROM your_table GROUP BY year;This query will extract the year from a date column in your table, and then count the occurrences of each unique year. The result will be a list of years and their corresponding count in the table.[rating:fb1c48f9-d45d-4887-9bae-8f42148c208d]What is a common table expression (CTE) in PostgreSQL.
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4 min readTo concatenate two tables in PostgreSQL, you can use the UNION operator. This operator allows you to combine the results of two separate SELECT statements into a single result set. When using UNION, both tables must have the same number of columns and corresponding columns should have compatible data types. Additionally, UNION removes any duplicate rows from the final result set.
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4 min readTo export a JSONB column in PostgreSQL, you can use the jsonb_to_json function to convert the JSONB data into JSON format. Then, you can use the jsonb_pretty function if you want to pretty print the JSON data. Finally, you can use the COPY command to export the JSON data to a file or another location. By combining these functions and commands, you can easily export JSONB data from a PostgreSQL table.
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3 min readIn PostgreSQL, you can convert a bigint value representing a timestamp into a formatted date string using the TO_TIMESTAMP function along with the TO_CHAR function.First, you need to cast the bigint value to a timestamp using the TO_TIMESTAMP function. For example, if your bigint value is stored in a column named "timestamp_column" in a table called "example_table", you can convert it to a timestamp like this:TO_TIMESTAMP(example_table.
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4 min readTo count every entry for each day in PostgreSQL, you can use the GROUP BY clause in combination with the COUNT function. By grouping the entries by the date field and then using COUNT, you can easily determine the number of entries for each day. Remember to also include the appropriate date formatting function to extract the date from the timestamp column if needed. Additionally, you can further filter the results by specific dates or date ranges by using the WHERE clause in your query.
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5 min readTo select from a variable in PostgreSQL, you first need to declare and set the variable using the PL/pgSQL language. This can be done using the := operator. Once the variable is set, you can then use it in your SQL query by referencing the variable name.
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8 min readIn PostgreSQL, you can use multiple partitions to store your data in a more organized manner. This can help with managing large amounts of data more efficiently. To use multiple partitions in PostgreSQL, you first need to create a partitioned table. This table will act as the parent table for your partitions.Next, you need to create child tables that will hold the actual data for each partition.
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3 min readTo select from a variable in PostgreSQL, you can use the SELECT statement along with the variable name. You need to declare the variable first using the DO $$ syntax. Then you can assign a value to the variable within the PostgreSQL PL/pgSQL block. Once the variable is defined and assigned a value, you can use it in your SELECT statement to retrieve data from the database based on the variable's value.