![](\"https:\/\/www.farukerdem.com\/wp-content\/uploads\/2021\/01\/functionpostgres.png\")
<\/p>\n
Let’s talk a little about our function mentioned above.<\/p>\n
create function sayitoplama(sayi1 int,sayi2 int)\r\nreturns integer\r\nlanguage plpgsql \r\nas\r\n$$\r\ndeclare \r\nsonuc integer;\r\nbegin \r\nsonuc:=sayi1+sayi2;\r\nreturn sonuc;\r\nend;\r\n$$;<\/pre>\ncreate function sayitoplama(sayi1 int, sayi2 int):<\/strong> After the create function, we enter the function name and the variable names given in parentheses and the data types of these variables.<\/p>\n
returns integer:<\/strong> We write the data type that will be returned as a result of the function.<\/p>\n
language plpgsql:<\/strong> We select the language to be used in the function.<\/p>\n
declare:<\/strong> In this section, we enter the variable name and data type that we will use in the function.<\/p>\n
begin-end:<\/strong> We write the necessary plpgsql commands for the operations to be performed between the begin-end block.<\/p>\n
Let’s write a function that converts the values entered in uppercase letters to lowercase letters and the letters containing “\u0131,\u015f,\u00e7,\u00f6,\u011f,\u00fc” into “i,\u015f,\u00f6,g,u” respectively.<\/p>\n
CREATE OR REPLACE FUNCTION TR_karakter ( metin VARCHAR(100) )\r\nRETURNS VARCHAR(100)\r\nLANGUAGE plpgsql\r\nAS\r\n$$\r\nDECLARE\r\nd2 VARCHAR(100);\r\nBEGIN\r\n d2 =metin;\r\n d2 = LOWER(d2);\r\n d2 = REPLACE(d2,'\u0131','i');\r\n d2 = REPLACE(d2,'\u015f','s');\r\n d2 = REPLACE(d2,'\u00e7','c');\r\n d2 = REPLACE(d2,'\u00f6','o');\r\n d2 = REPLACE(d2,'\u011f','g');\r\n d2 = REPLACE(d2,'\u00fc','u');\r\n return (d2);\r\nEND<\/pre>\n<\/div>\n