How to do it...

1. Open the console and create the folder chapter02/recipe03.
2. Navigate to the directory.
3. Create the join.go file with the following content:

        package main

        import (
          "fmt"
          "strings"
        )

        const selectBase = "SELECT * FROM user WHERE %s "

        var refStringSlice = []string{
          " FIRST_NAME = 'Jack' ",
          " INSURANCE_NO = 333444555 ",
          " EFFECTIVE_FROM = SYSDATE "}

        func main() {

          sentence := strings.Join(refStringSlice, "AND")
          fmt.Printf(selectBase+"\n", sentence)

        }

1. Run the code by executing go run join.go.
2. See the output in the Terminal:

1. Create the join_manually.go file with the following content:

        package main

        import (
          "fmt"
          "strings"
        )

        const selectBase = "SELECT * FROM user WHERE "

        var refStringSlice = []string{
          " FIRST_NAME = 'Jack' ",
          " INSURANCE_NO = 333444555 ",
          " EFFECTIVE_FROM = SYSDATE "}

        type JoinFunc func(piece string) string

        func main() {

          jF := func(p string) string {
            if strings.Contains(p, "INSURANCE") {
              return "OR"
            }

            return "AND"
          }
          result := JoinWithFunc(refStringSlice, jF)
          fmt.Println(selectBase + result)
        }
 
         func JoinWithFunc(refStringSlice []string,
                           joinFunc JoinFunc) string {
           concatenate := refStringSlice[0]
           for _, val := range refStringSlice[1:] {
             concatenate = concatenate + joinFunc(val) + val
           }
           return concatenate
        }

1. Run the code by executing go run join.go.
2. See the output in the Terminal: