CASE WHEN condition THEN result [WHEN ...] [ELSE result] END CASE clauses can be used wherever an expression is valid. Column names that were created with double-quotes and thereby retained upper-case letters (and/or other syntax violations) have to be double-quoted for the rest of their life. When I first migrated, one problem I had was related to how string columns work. Case insensitive column names in a postgresql trigger function. It’s important to note here that here when we say “create,” we merely mean in our returned recordset. Summary: in this tutorial, you will learn about PostgreSQL column aliases and how to use column aliases to assign temporary names to columns in queries.. Introduction to the PostgreSQL column aliases. February 10, 2015 . The column alias exists temporarily during the execution of the query. Quoting an identifier also makes it case-sensitive, whereas unquoted names are always folded to lower case.For example, the identifiers FOO, foo, and "foo" are considered the same by PostgreSQL, but "Foo" and "FOO" are different from these three and each other. Besides the type CAST syntax, you can use the following syntax to convert a value of one type into another: Now we’ll use the “CASE” statement to also return a new column called t_honorific. Here we will create a new function named get_price_segment that accepts p_film_id as the argument. Projection: Select the columns in a table that are returned by a query. Now, if you still insist to convert to upper case, you can do that by dumping your database schema into a file using pg_dump --schema-only . If, on other hand, you use standard PostgreSQL lower-case only agreement, you can use any case combination and it will work as long as you do not quote any name. In this case, the combination of values in both column1 and column2 columns will be used for evaluating the duplicate.. PostgreSQL also provides the DISTINCT ON (expression) to keep the “first” row of each group of duplicates using the following syntax: put table name into double quotes if you want postgres to preserve case for relation names. Ask Question Asked 30 days ago. Read in 3 minutes. To convert a string, an expression, or values in a column to lower case, you use the LOWER case function. The following illustrates the syntax of the LOWER function: Using insensitive-case columns in PostgreSQL with citext. By Nando Vieira. In case the price is not 0.99, 2.99 or 4.99, the function returns unspecified. Summary: in this tutorial we will show you how to use the LOWER, UPPER and INITCAP functions to convert a string expression, values in a column, etc., to lowercase, uppercase, and proper case.. PostgreSQL LOWER function. Based on the rental rate of the film, it returns the price segment: mass, mainstream, high end. The SQL CASE expression is a generic conditional expression, similar to if/else statements in other programming languages:. Viewed 58 times 3. CASE. Each condition is an expression that returns a boolean result. A column alias allows you to assign a column or an expression in the select list of a SELECT statement a temporary name. Selection: Select the rows in a table that are returned by a query. Active 27 days ago. Note, this new column does not exist in our “Users” table; we are using “CASE” to create this new column (field) on the fly. select as few or as many of the columns required. In this post, we are going to learn about PostgreSQL Select statement.A SQL select statement retrieves information from the database.With a SELECT statement, you can use the following capabilities. First, specify an expression that can be a constant, a table column, an expression that evaluates to a value. 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