Example 3: Using CASE WHEN in an UPDATE Statement Code: -- Update employee bonuses based on their performance UPDATE employees SET bonus = CASE WHEN performance_rating = 'Excellent' THEN 1000 WHEN performance_r
SELECTCASEatttypidWHEN21/*int2*/THEN16WHEN23/*int4*/THEN32WHEN20/*int8*/THEN64WHEN1700/*numeric*/THENCASEWHENatttypmod=-1THENnullELSE((atttypmod-4)>>16)&65535--calculate the precisionENDWHEN700/*float4*/THEN24/*FLT_MANT_DIG*/WHEN701/*float8*/THEN53/*DBL_MANT_DIG*/ELSEnullENDA...
Example 2: How Does the Simple CASE Statement Work in Postgres? The following snippet demonstrates the working of the simple CASE statement: SELECTauthor_name, author_exp,CASEgenderWHEN'M'THEN'Male'WHEN'F'THEN'Female'ENDCASEFROMauthor_infoORDERBYauthor_idASC; In the above snippet, the CASE st...
in 'http://www.example.com/filename.txt') + 1); 输出结果：20步骤3：截取子字符串现在我们可以使用 SUBSTRING 函数来截取字符串。我们将把第二个正斜杠的位置作为位置参数传递给 SUBSTRING 函数，然后从第一个正斜杠之后截取子字符串。sql SELECT substring('http://www.example.com/filename.txt' from...
一:理论 oracle 截取字符(substr),检索字符位置(instr) case when then else end语句使用 收藏 常用函数:substr和instr 1.SUBSTR(string,start_position,[length]) 求子字符串,返回字符串 解释:string 元字符串 start_position 开始位置(从0开始) length 可选项,子字符串的个数 For example: substr("ABCDEFG",...
Simple CASE Example Suppose you have a table students with a column grades. If you want to classify students based on their grades, a Simple CASE can be handy. Query Demonstration SELECT name, grade, CASE grade WHEN 'A' THEN 'Excellent' WHEN 'B' THEN 'Good' WHEN 'C' THEN 'Average' ...
An example: GET DIAGNOSTICS integer_var = ROW_COUNT; The second method to determine the effects of a command is to check the special variable named FOUND, which is of type boolean. FOUND starts out false within each PL/pgSQLfunction call. It is set by each of the following types of sta...
For example, if you choose to have one partition per customer and you currently have a small number of large customers, consider the implications if in several years you instead find yourself with a large number of small customers. In this case, it may be better to choose to partition by ...
In PostgreSQL, ICU locales can be used by creating one in the database using theCREATE COLLATIONcommand. An example is: CREATE COLLATION english (provider = icu, locale = 'en-US'); The basic structure of ICU collation names is simliar to that of libc collations: a language code, followed...
GRANT ALL PRIVILEGES ON DATABASE exampledb TO dbuser; now转换成time without time zone: select now()::timestamp without time zone select now(),now()::timestamp(0)+interval '1 day'; select date '2019-07-09' +interval '1 day'; ...