Function buildBetweenClause

dumpling/export/sql.go:1150–1206

buildBetweenClause build clause in a specified table range. the result where clause will be low <= quotaCols < up. In other words, [low, up)

(buf *bytes.Buffer, quotaCols []string, low []string, up []string)

// buildBetweenClause build clause in a specified table range.
// the result where clause will be low <= quotaCols < up. In other words, [low, up)
func buildBetweenClause(buf *bytes.Buffer, quotaCols []string, low []string, up []string) {
	singleBetween := func(writeEqual bool) {
		buf.WriteString(quotaCols[0])
		buf.WriteByte(greater)
		if writeEqual {
			buf.WriteByte(equal)
		}
		buf.WriteString(low[0])
		buf.WriteString(" and ")
		buf.WriteString(quotaCols[0])
		buf.WriteByte(less)
		buf.WriteString(up[0])
	}
	// handle special cases with common prefix
	commonLen := getCommonLength(low, up)
	if commonLen > 0 {
		// unexpected case for low == up, return empty result
		if commonLen == len(low) {
			buf.WriteString("false")
			return
		}
		for i := 0; i < commonLen; i++ {
			if i > 0 {
				buf.WriteString(" and ")
			}
			buf.WriteString(quotaCols[i])
			buf.WriteByte(equal)
			buf.WriteString(low[i])
		}
		buf.WriteString(" and(")
		defer buf.WriteByte(')')
		quotaCols = quotaCols[commonLen:]
		low = low[commonLen:]
		up = up[commonLen:]
	}

	// handle special cases with only one column
	if len(quotaCols) == 1 {
		singleBetween(true)
		return
	}
	buf.WriteByte('(')
	singleBetween(false)
	buf.WriteString(")or(")
	buf.WriteString(quotaCols[0])
	buf.WriteByte(equal)
	buf.WriteString(low[0])
	buf.WriteString(" and(")
	buildCompareClause(buf, quotaCols[1:], low[1:], greater, true)
	buf.WriteString("))or(")
	buf.WriteString(quotaCols[0])
	buf.WriteByte(equal)
	buf.WriteString(up[0])
	buf.WriteString(" and(")
	buildCompareClause(buf, quotaCols[1:], up[1:], less, false)
	buf.WriteString("))")
}