12/2/2023 0 Comments Case sql postgres![]() ![]() Here is a proof of concept.īut, honestly, I'd rather avoid the complication and just use the simple query above. You want a simple call like this? SELECT * FROM f_tbl_counts_6months(NULL::m6_jul) But do you actually need the pivoted form? OK, you asked for it. The PostgreSQL CASE expression is the same as IF/ELSE statement in other programming languages. Well, you could prepare 12 different row types (that's the range of possible result types for your case) and use a polymorphic function to achieve it. If you really need that, you need a 2-step flow of operation (two round trips to the server): But dynamic column names are not possible for a static SQL query. Your original query produces that information in pivoted form: one month per column. Using standard English month names and 3-letter-abbreviations. Query with LEFT JOIN not returning rows for count of 0.Note, in particular, that it's faster to aggregate first and join later. PostgreSQL: running count of rows for a query 'by minute'.COALESCE makes the count 0 instead of NULL for that case. You can apply LOWER() to the name and all values as well to compare in a case insensitive manner. 205 1 1 silver badge 13 13 bronze badges. ![]() This way always returns the last 6 months, even if no rows are found at all. postgresql case-insensitive sql-in Share. Then LEFT JOIN to counts per month from the relevant time range. Generating time series between two dates in PostgreSQL.If the case statement finds a match, it will execute the corresponding. The case statement compares the result of the search-expression with the expression in each when branch using equal operator ( ) from top to bottom. Google Cloud recently announced the Cloud SQL Enterprise Plus edition for MySQL and PostgreSQL of the managed database service. Note how I first build timestamps for the last six months (excluding the current one) with generate_series() in the first subquery mon. Code language: PostgreSQL SQL dialect and PL/pgSQL (pgsql) The search-expression is an expression that evaluates to a result. Returns one row per month, in chronological order (considering the year, too, though it's not in your output!), and truly dynamic. (I'd rather not use start as column name as that's a keyword in standard SQL - even if allowed in Postgres.) SELECT date_trunc('month', start) AS mon, count(*) AS ctĪND start = c.current_mon - interval '6 mon' You'd need to use a subquery to get the result: select stops, count () Total from ( select CASE when Stops in ('1Stop', '1 Stop', '1 stop') then '1-Stop' ELSE Stops END as Stops from yourtable ) d group by stops See SQL Fiddle with Demo. WHERE CASE WHEN x 0 THEN y/x > 1.The column month seems to be redundant. For example, this is a possible way of avoiding a division-by-zero failure: SELECT. The example above can be written using the simple CASE syntax: SELECT a,Ī CASE expression does not evaluate any subexpressions that are not needed to determine the result. This is similar to the switch statement in C. If no match is found, the result of the ELSE clause (or a null value) is returned. The first expression is computed, then compared to each of the value expressions in the WHEN clauses until one is found that is equal to it. There is a "simple" form of CASE expression that is a variant of the general form above: CASE expression The data types of all the result expressions must be convertible to a single output type. If the ELSE clause is omitted and no condition is true, the result is null. If no WHEN condition yields true, the value of the CASE expression is the result of the ELSE clause. If the condition's result is not true, any subsequent WHEN clauses are examined in the same manner. If the condition's result is true, the value of the CASE expression is the result that follows the condition, and the remainder of the CASE expression is not processed. Each condition is an expression that returns a boolean result. The SQL CASE expression is a generic conditional expression, similar to if/else statements in other programming languages: CASE WHEN condition THEN resultĬASE clauses can be used wherever an expression is valid. Case statements are useful when youre reaching for an if statement in your select clause. ![]()
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